Sony FE 12-24mm f/2.8 GM Review
p.16 #1Sony FE 12-24mm f/2.8 GM Review
inksandpaper wrote:
That's strange. Shimming tilt at the mount does not cause FC to increase significantly. I wonder what's going on. What do you mean by the focus distance reported was less accurate? How much less accurate was it? Is it commensurate with the focus shift you would expect on-axis for a 10-micron correction induced at the screw, which is ~5 microns only on-axis?
Yes, I was susprised to see the induced FC given how thin the shim was. Past about 1m, the in-camera distance readout was increased significantly. E.g. objects at ~2m were sharpest for a readout of about 4m, whereas unshimmed it was actually surprisingly accurate. I rely on such distance readouts to do my focus stacking, so this strange readout remapping might make that quite challenging. I'm not sure how to calculate how much focus shift I should expect.
But the whole affair has remined me why I was so glad to see more high IQ native lenses released for the Sony E system after messing around with shimmed adapters in the early days.
** edit *** Maybe I'm underestimating the shim thickness due to the lens mount screws exerting less compressive force than I think. But I don't think it could be more than 20um. Whatever the effective thickness was, it was about the right amount to balance corner sharpness, so not a viable solution for me due to the FC and distance readout problems.
Edited on Sep 16, 2020 at 04:22 PM · View previous versions
That's strange. Shimming tilt at the mount does not cause FC to increase significantly. I wonder what's going on. What do you mean by the focus distance reported was less accurate? How much less accurate was it? Is it commensurate with the focus shift you would expect on-axis for a 10-micron correction induced at the screw, which is ~5 microns only on-axis?
Yes, I was susprised to see the induced FC given how thin the shim was. Past about 1m, the in-camera distance readout was increased significantly. E.g. objects at ~2m were sharpest for a readout of about 4m, whereas unshimmed it was actually surprisingly accurate. I rely on such distance readouts to do my focus stacking, so this strange readout remapping might make that quite challenging. I'm not sure how to calculate how much focus shift I should expect.
But the whole affair has remined me why I was so glad to see more high IQ native lenses released for the Sony E system after messing around with shimmed adapters in the early days.
** edit *** Maybe I'm underestimating the shim thickness due to the lens mount screws exerting less compressive force than I think. But I don't think it could be more than 20um. Whatever the effective thickness was, it was about the right amount to balance corner sharpness, so not a viable solution for me due to the FC and distance readout problems.
Edited on Sep 16, 2020 at 04:22 PM · View previous versions
Sep 16, 2020 at 04:07 PM
p.16 #2Sony FE 12-24mm f/2.8 GM Review
Tristan.W wrote:
There is definately a consistent tilt/swing that has improved across the whole range with the shim I installed. But in addition to that, the lower left corner does seem slightly weaker (perhaps a little more astigmatism) even when each corner is focused on in turn. I'm really on the fence with this copy. I know it could be better but it could be a whole lot worse too, and stopped down a bit it's fine.Does that softer corner improve when focusing on it? If not, the lens could have a decentered element as well.
Shimming can fix with focal plane tilt/swing but it won't be useful if the lens is decentered.
A fellow FM member just emailed me his centering test and his lens looked excellent at 12mm and 24mm.I received mine this AM and thoroughly tested it. The lower-left corner is ever so slightly out (almost imperceptible), but not enough to ever worry about. Overall, this is an outstanding lens! Whew!! Well done, Sony.
I can see where this will likely become on of my favorite lenses and it (along with the GM135 and a few ART lenses) might even keep me from ordering an R5.
Congratulations on the lens. I agree this lens pretty much eliminates the need to carry anything else in its range (if you get a good one). I am really impressed by its ability to shoot against the sun, and have no problems with its color palette unlike the F4.Congratulations to you both for satisfified copies!
it's not easy to exchange till a well banlanced copy here. I decide to wait for 1 more year to try my luck
Unfortunately I don't have a copy I'm satisfied with yet. #4 is on its way to me, but I'm not at all confident anymore that it will be my last one.
rvh23 wrote
InFocus2014 wrote
Fred Miranda wrote
rvh23 wrote
Fred Miranda wrote
Is the lens decentered or focal plane tilted? The best way to find out is to focus at the very corners individually and compare them. If they corners look equal, the lens is not decentered and there is hope of fixing the asymmetry. The trick with zooms is that as we change focal length, the focal plane usually gets swung or tilted and therefore shims may not work for all FLs.Shimming can fix with focal plane tilt/swing but it won't be useful if the lens is decentered.
A fellow FM member just emailed me his centering test and his lens looked excellent at 12mm and 24mm.
I can see where this will likely become on of my favorite lenses and it (along with the GM135 and a few ART lenses) might even keep me from ordering an R5.
it's not easy to exchange till a well banlanced copy here. I decide to wait for 1 more year to try my luck
Unfortunately I don't have a copy I'm satisfied with yet. #4 is on its way to me, but I'm not at all confident anymore that it will be my last one.
Sep 16, 2020 at 04:10 PM
p.16 #3Sony FE 12-24mm f/2.8 GM Review
rvh23 wrote:
Yes, I was susprised to see the induced FC given how thin the shim was. Past about 1m, the in-camera distance readout was increased significantly. E.g. objects at ~2m were sharpest for a readout of about 4m, whereas unshimmed it was actually surprisingly accurate. I rely on such distance readouts to do my focus stacking, so this strange readout remapping might make that quite challenging. I'm not sure how to calculate how much focus shift I should expect.
** edit *** Maybe I'm underestimating the shim thickness due to the lens mount screws exerting less compressive force than I think....Show more →
A focus shift from 2 to 4 meters for 12mm focal length is 36 microns of extension on-axis. For 24mm focal length it is 146 microns. The difference is quite huge. It implies your shim could be as thick as 300(!!) microns. It's certainly not ~5-10 microns worth on-axis (you say you think your shim thickness cannot be more than 20 mics, so you also are saying it cannot be more than 10 mics on-axis). You can use my lens extensions calculator to work it out for yourself: https://www.dropbox.com/s/h63qai5me3zt3u6/Lens%20Extension%20Calculator.xlsx?dl=0
You might have seen Roger Cicala's flange distance articles where he measured thousands of cameras, and 487 Sony E-mount cameras. The variation of Sony E-mount flange distance, excluding far outliers, spans about 100 microns. Alpha 7 series cameras alone were about 60-70 microns in variation on-axis. In fact, it is remarkable that any lens, without calibration to a user's specific camera, could guarantee accurate focus distance readouts unless you got lucky. I wouldn't consider this a fault since it is easily adjusted by a service center. It is not so good to depend on this readout for focus stacking, I've never found it to be precise enough. I would recommend to use focus peaking indication. Hopefully one day Sony will program automatic focus stacking into their cameras.
https://www.lensrentals.com/blog/2020/06/the-great-flange-to-sensor-distance-article-part-ii-photo-cameras/
Yes, I was susprised to see the induced FC given how thin the shim was.
Maybe there was an observational error? Do you have the full resolution before and after test shots that demonstrate this severe field curvature that was induced by your shimming?
Anyway, don't take my word for it. Here were Brandon Dube's comments on field curvature vs spacing across various comments on the Lensrentals blog, from which I understood that spacing and alignment does not affect field curvature:
The mechanism of misalignment in a lens determines how its MTF departs from the average or nominal value. A spacing error will cause a relatively uniform error across the field of view because it changes only spherical aberration and axial color, aberrations that are constant over the field. There is a balance between aberrations so it is not precisely uniform over the field, but for small changes the aberrations are reasonably orthogonal.
Also:
Surfaces are not equal for different purposes. If you want to image on a flat surface, you absolutely must have both positive and negative powered elements for the Petzval sum to be anywhere near zero. If you curve the image, you don’t need negative lenses anymore because the image plane can curve as the positive lenses want it to. This means you can delete the negative lenses, which probably injected aberrations into your design anyway.
Or, in the more general case, it gives you a knob that is essentially a 1:1 control over field curvature. Where you may have had 5, maybe 10 elements all fighting each other to get near zero field curvature otherwise.
This makes the curved image surface as valuable as several other elements, not just parameters, in the design.
And:
The reason the image is curved is first and foremost because of "petzval curvature," which has a design type named after it, since that is the only primary aberration the design does not correct for. Petzval curvature comes simply from the positive focal length of the elements and is, as a result, not very sensitive to alignment.
Next from petzval you have "astigmatism," which affects the tangential ray fan three times more than the sagittal because of geometry. It's obvious, then, that the design should immediately manifest any perturbation of astigmatism three times more strongly in T than S. Then you have the designer's efforts, where they introduce "tangential astigmatism" or "sagittal astigmatism" to flatten the field. They need three times as much of this pill to bring T on top of S, and generally the more aberration you put in, the more sensitivity you get, too.
And:
Astigmatism and field curvature are invariant with aperture. They are reduced in apparent magnitude when the aperture is closed, because the depth of field is increased. If a lens has focus shift from spherical aberration, the plane selected in the MTFvFvF plots may move to one that is more astigmatic (e.g. if the T and S fields move away at the edge, which is what astigmatism is).
The separation of the T and S lines in an MTF vs Field plot is not directly indicative of astigmatism; there can be several causes for that (astigmatism being one of them.)
Yes, I was susprised to see the induced FC given how thin the shim was. Past about 1m, the in-camera distance readout was increased significantly. E.g. objects at ~2m were sharpest for a readout of about 4m, whereas unshimmed it was actually surprisingly accurate. I rely on such distance readouts to do my focus stacking, so this strange readout remapping might make that quite challenging. I'm not sure how to calculate how much focus shift I should expect.
** edit *** Maybe I'm underestimating the shim thickness due to the lens mount screws exerting less compressive force than I think....Show more →
A focus shift from 2 to 4 meters for 12mm focal length is 36 microns of extension on-axis. For 24mm focal length it is 146 microns. The difference is quite huge. It implies your shim could be as thick as 300(!!) microns. It's certainly not ~5-10 microns worth on-axis (you say you think your shim thickness cannot be more than 20 mics, so you also are saying it cannot be more than 10 mics on-axis). You can use my lens extensions calculator to work it out for yourself: https://www.dropbox.com/s/h63qai5me3zt3u6/Lens%20Extension%20Calculator.xlsx?dl=0
You might have seen Roger Cicala's flange distance articles where he measured thousands of cameras, and 487 Sony E-mount cameras. The variation of Sony E-mount flange distance, excluding far outliers, spans about 100 microns. Alpha 7 series cameras alone were about 60-70 microns in variation on-axis. In fact, it is remarkable that any lens, without calibration to a user's specific camera, could guarantee accurate focus distance readouts unless you got lucky. I wouldn't consider this a fault since it is easily adjusted by a service center. It is not so good to depend on this readout for focus stacking, I've never found it to be precise enough. I would recommend to use focus peaking indication. Hopefully one day Sony will program automatic focus stacking into their cameras.
https://www.lensrentals.com/blog/2020/06/the-great-flange-to-sensor-distance-article-part-ii-photo-cameras/
Yes, I was susprised to see the induced FC given how thin the shim was.
Maybe there was an observational error? Do you have the full resolution before and after test shots that demonstrate this severe field curvature that was induced by your shimming?
Anyway, don't take my word for it. Here were Brandon Dube's comments on field curvature vs spacing across various comments on the Lensrentals blog, from which I understood that spacing and alignment does not affect field curvature:
The mechanism of misalignment in a lens determines how its MTF departs from the average or nominal value. A spacing error will cause a relatively uniform error across the field of view because it changes only spherical aberration and axial color, aberrations that are constant over the field. There is a balance between aberrations so it is not precisely uniform over the field, but for small changes the aberrations are reasonably orthogonal.
Also:
Surfaces are not equal for different purposes. If you want to image on a flat surface, you absolutely must have both positive and negative powered elements for the Petzval sum to be anywhere near zero. If you curve the image, you don’t need negative lenses anymore because the image plane can curve as the positive lenses want it to. This means you can delete the negative lenses, which probably injected aberrations into your design anyway.
Or, in the more general case, it gives you a knob that is essentially a 1:1 control over field curvature. Where you may have had 5, maybe 10 elements all fighting each other to get near zero field curvature otherwise.
This makes the curved image surface as valuable as several other elements, not just parameters, in the design.
And:
The reason the image is curved is first and foremost because of "petzval curvature," which has a design type named after it, since that is the only primary aberration the design does not correct for. Petzval curvature comes simply from the positive focal length of the elements and is, as a result, not very sensitive to alignment.
Next from petzval you have "astigmatism," which affects the tangential ray fan three times more than the sagittal because of geometry. It's obvious, then, that the design should immediately manifest any perturbation of astigmatism three times more strongly in T than S. Then you have the designer's efforts, where they introduce "tangential astigmatism" or "sagittal astigmatism" to flatten the field. They need three times as much of this pill to bring T on top of S, and generally the more aberration you put in, the more sensitivity you get, too.
And:
Astigmatism and field curvature are invariant with aperture. They are reduced in apparent magnitude when the aperture is closed, because the depth of field is increased. If a lens has focus shift from spherical aberration, the plane selected in the MTFvFvF plots may move to one that is more astigmatic (e.g. if the T and S fields move away at the edge, which is what astigmatism is).
The separation of the T and S lines in an MTF vs Field plot is not directly indicative of astigmatism; there can be several causes for that (astigmatism being one of them.)
Sep 16, 2020 at 05:22 PM
p.16 #4Sony FE 12-24mm f/2.8 GM Review
inksandpaper wrote:
A focus shift from 2 to 4 meters for 12mm focal length is 36 microns of extension on-axis. For 24mm focal length it is 146 microns. The difference is quite huge. It implies your shim could be as thick as 300(!!) microns. It's certainly not ~5-10 microns worth on-axis (you say you think your shim thickness cannot be more than 20 mics, so you also are saying it cannot be more than 10 mics on-axis). You can use my lens extensions calculator to work it out for yourself: https://www.dropbox.com/s/h63qai5me3zt3u6/Lens%20Extension%20Calculator.xlsx?dl=0
You might have seen Roger Cicala's flange distance articles where he measured...Show more →
Thanks very much for all this additional information and taking the time.
I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.
When you say the spacing and allignment shouldn't affect FC, I don't at all doubt your expertise, and even less so the folks at lensrenatals. But my recollection of my adapter shimming days, and also discussion here on FM, is that FC often was affected. But it's possible I'm misremembering the details.
A focus shift from 2 to 4 meters for 12mm focal length is 36 microns of extension on-axis. For 24mm focal length it is 146 microns. The difference is quite huge. It implies your shim could be as thick as 300(!!) microns. It's certainly not ~5-10 microns worth on-axis (you say you think your shim thickness cannot be more than 20 mics, so you also are saying it cannot be more than 10 mics on-axis). You can use my lens extensions calculator to work it out for yourself: https://www.dropbox.com/s/h63qai5me3zt3u6/Lens%20Extension%20Calculator.xlsx?dl=0
You might have seen Roger Cicala's flange distance articles where he measured...Show more →
Earlier quote
Yes, I was susprised to see the induced FC given how thin the shim was.Thanks very much for all this additional information and taking the time.
I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.
When you say the spacing and allignment shouldn't affect FC, I don't at all doubt your expertise, and even less so the folks at lensrenatals. But my recollection of my adapter shimming days, and also discussion here on FM, is that FC often was affected. But it's possible I'm misremembering the details.
Sep 16, 2020 at 07:44 PM
p.16 #5Sony FE 12-24mm f/2.8 GM Review
rvh23 wrote:
Thanks very much for all this additional information and taking the time.
I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens...Show more →
No problem! Yes, I am doubtful that the shimming material is that thick. The degree of misalignment looks subtle, less than 50 microns by my very rough estimate. But it also looks decentered, not just tilted or swung, again I'm guessing from your crops. One needs to see the full image and the test subject needs to have certain qualities for one to be absolutely sure.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were grossly asymmetrical. I tried only one and it was too. That's 9 out of 9 all bad, and not slightly bad. Like really bad. I have no idea how anyone gets good copies, surely our luck cannot be this awful. Fred seems to have an amazing copy to kill for. I recall seeing one other great copy on this forum. Joe remembers seeing two others, so we know of a total of 4 copies that are supposedly really great, but we can't seem to find them (I've given up myself, since I don't usually shoot super wide anyways). One would hope the GMs are a little more consistent in that regard, given the cost. Cameras today are too sharp and unforgiving on the optics.
When you say the spacing and allignment shouldn't affect FC, I don't at all doubt your expertise, and even less so the folks at lensrenatals. But my recollection of my adapter shimming days, and also discussion here on FM, is that FC often was affected. But it's possible I'm misremembering the details.
I too remember seeing such statements here from time to time, which has always puzzled me that folks were observing such a phenomenon. Sounded like observational error then.
Thanks very much for all this additional information and taking the time.
I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens...Show more →
No problem! Yes, I am doubtful that the shimming material is that thick. The degree of misalignment looks subtle, less than 50 microns by my very rough estimate. But it also looks decentered, not just tilted or swung, again I'm guessing from your crops. One needs to see the full image and the test subject needs to have certain qualities for one to be absolutely sure.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were grossly asymmetrical. I tried only one and it was too. That's 9 out of 9 all bad, and not slightly bad. Like really bad. I have no idea how anyone gets good copies, surely our luck cannot be this awful. Fred seems to have an amazing copy to kill for. I recall seeing one other great copy on this forum. Joe remembers seeing two others, so we know of a total of 4 copies that are supposedly really great, but we can't seem to find them (I've given up myself, since I don't usually shoot super wide anyways). One would hope the GMs are a little more consistent in that regard, given the cost. Cameras today are too sharp and unforgiving on the optics.
When you say the spacing and allignment shouldn't affect FC, I don't at all doubt your expertise, and even less so the folks at lensrenatals. But my recollection of my adapter shimming days, and also discussion here on FM, is that FC often was affected. But it's possible I'm misremembering the details.
I too remember seeing such statements here from time to time, which has always puzzled me that folks were observing such a phenomenon. Sounded like observational error then.
Sep 16, 2020 at 08:33 PM
p.16 #6Sony FE 12-24mm f/2.8 GM Review
inksandpaper wrote:
I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.No problem! Yes, I am doubtful that the shimming material is that thick. The degree of misalignment looks subtle, less than 50 microns by my very rough estimate. But it also looks decentered, not just tilted or swung, again I'm guessing from your crops. One needs to see the full image and the test subject needs to have certain qualities for one to be absolutely sure.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were...Show more →
It took me four copies before I had a Sigma 14-24 DG DN that I was happy with, and I thought I was having worse luck than most, but perhaps not judging from your comment.
Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil (so maybe 40um) in the most-adjusted corner. Results showed about the same improvement as for my internal shimming exercise, but the distance readout and FC were not noticeably affected now.
It's now very good at 14mm, not bad at 12mm, but all four corners are softer than I'd like at the long end. My 2nd copy was actually superb at 24mm, but at the wide end had one corner that didn't sharpen up enough even stopped down. So the search continues.
I've pretty much commited to trying as many copies as it takes (hopefully not 10) because this focal range is where I shoot the very large majority of my landscapes.
rvh23 wrote
Thanks very much for all this additional information and taking the time.I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were...Show more →
Earlier quote
When you say the spacing and allignment shouldn't affect FC, I don't at all doubt your expertise, and even less so the folks at lensrenatals. But my recollection of my adapter shimming days, and also discussion here on FM, is that FC often was affected. But it's possible I'm misremembering the details.It took me four copies before I had a Sigma 14-24 DG DN that I was happy with, and I thought I was having worse luck than most, but perhaps not judging from your comment.
Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil (so maybe 40um) in the most-adjusted corner. Results showed about the same improvement as for my internal shimming exercise, but the distance readout and FC were not noticeably affected now.
It's now very good at 14mm, not bad at 12mm, but all four corners are softer than I'd like at the long end. My 2nd copy was actually superb at 24mm, but at the wide end had one corner that didn't sharpen up enough even stopped down. So the search continues.
I've pretty much commited to trying as many copies as it takes (hopefully not 10) because this focal range is where I shoot the very large majority of my landscapes.
Sep 16, 2020 at 09:19 PM
p.16 #7Sony FE 12-24mm f/2.8 GM Review
Damn didn't know the amount of bad copies with the sigma 14-24 2.8 was that high. Good luck on the good copy 12-24 gm search. Maybe have Fred get one since he has some hidden magic and then have him just sell you the good copy I wonder how good the lenses are for say like a 100mp gfx 100. They get bad copies?
I wonder how good the lenses are for say like a 100mp gfx 100. They get bad copies? Sep 17, 2020 at 12:44 AM
p.16 #8Sony FE 12-24mm f/2.8 GM Review
sismailian wrote:
Damn didn't know the amount of bad copies with the sigma 14-24 2.8 was that high. Good luck on the good copy 12-24 gm search. Maybe have Fred get one since he has some hidden magic and then have him just sell you the good copy I wonder how good the lenses are for say like a 100mp gfx 100. They get bad copies?
No magic -- just luck receiving optimal copies at first try.
With zooms, one can try 5-10 copies and still not get an optimal copy...and even if you get a great one, it will never be perfect.
Because there is tolerance in lens production, once we get 200MP sensors, we will see flaws in every lens even "perfect" primes. There is also the issue with mount-sensor parallelism to deal with so we must be realistic on what's acceptable.
Damn didn't know the amount of bad copies with the sigma 14-24 2.8 was that high. Good luck on the good copy 12-24 gm search. Maybe have Fred get one since he has some hidden magic and then have him just sell you the good copy
I wonder how good the lenses are for say like a 100mp gfx 100. They get bad copies? No magic -- just luck receiving optimal copies at first try.
With zooms, one can try 5-10 copies and still not get an optimal copy...and even if you get a great one, it will never be perfect.
Because there is tolerance in lens production, once we get 200MP sensors, we will see flaws in every lens even "perfect" primes. There is also the issue with mount-sensor parallelism to deal with so we must be realistic on what's acceptable.
Sep 17, 2020 at 10:41 AM
p.16 #9Sony FE 12-24mm f/2.8 GM Review
Fred Miranda wrote:
I wonder how good the lenses are for say like a 100mp gfx 100. They get bad copies? No magic -- just luck receiving optimal copies a first try.
With zooms, one can try 5-10 copies and still not get an optimal copy...and even if you get a great one, it will never be perfect.
Because there is tolerance in lens production, once we get 200MP sensors, we will see flaws in very lens even "perfect" primes. There is also the issue with mount-sensor parallelism to deal with so we must be realistic on what's acceptable.
I think we are already approaching that situation at 61MP. To put my ongoing quest for a good GM into perspective, if I were on 42MP or less, my last two copies of the GM might have been "good enough". The A7r4 really challenges even the best optics.
sismailian wrote
Damn didn't know the amount of bad copies with the sigma 14-24 2.8 was that high. Good luck on the good copy 12-24 gm search. Maybe have Fred get one since he has some hidden magic and then have him just sell you the good copy I wonder how good the lenses are for say like a 100mp gfx 100. They get bad copies? With zooms, one can try 5-10 copies and still not get an optimal copy...and even if you get a great one, it will never be perfect.
Because there is tolerance in lens production, once we get 200MP sensors, we will see flaws in very lens even "perfect" primes. There is also the issue with mount-sensor parallelism to deal with so we must be realistic on what's acceptable.
I think we are already approaching that situation at 61MP. To put my ongoing quest for a good GM into perspective, if I were on 42MP or less, my last two copies of the GM might have been "good enough". The A7r4 really challenges even the best optics.
Sep 17, 2020 at 04:06 PM
p.16 #10Sony FE 12-24mm f/2.8 GM Review
I agree with RVH - It's more challenging finding good enough copies of lenses on the A7RIV than on the A7RIII. More difficult than you would imagine given that the resolution difference isn't very significant - about 20% as I recall.
Sep 17, 2020 at 05:14 PM
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p.16 #11Sony FE 12-24mm f/2.8 GM Review
I guess that makes me be glad i didn't go for the a7r4 and went with the a7r3 42mp is a lot to be happy with. 😎👍 Can't wait to go out shoot this weekend a bit maybe.
42mp is a lot to be happy with. 😎👍 Can't wait to go out shoot this weekend a bit maybe.Sep 17, 2020 at 05:40 PM
p.16 #12Sony FE 12-24mm f/2.8 GM Review
rvh23 wrote:
Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil (so maybe 40um) in the most-adjusted corner. Results showed about the same improvement as for my internal shimming exercise, but the distance readout and FC were not noticeably affected now.
It's now very good...Show more →
I'm glad to hear that you didn't experience problems with FC and the focus distance readouts this time! Good luck with your search, I hope you find that elusive optimal copy...
Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil (so maybe 40um) in the most-adjusted corner. Results showed about the same improvement as for my internal shimming exercise, but the distance readout and FC were not noticeably affected now.
It's now very good...Show more →
I'm glad to hear that you didn't experience problems with FC and the focus distance readouts this time! Good luck with your search, I hope you find that elusive optimal copy...
Sep 17, 2020 at 07:44 PM
p.16 #13Sony FE 12-24mm f/2.8 GM Review
sismailian wrote:
I wonder how good the lenses are for say like a 100mp gfx 100. They get bad copies?
You bet. There are plenty of bad ones I've seen. There are crooked GFX cameras out there too.
I wonder how good the lenses are for say like a 100mp gfx 100. They get bad copies?
You bet. There are plenty of bad ones I've seen. There are crooked GFX cameras out there too.
Sep 17, 2020 at 07:44 PM
p.16 #14Sony FE 12-24mm f/2.8 GM Review
httivals wrote:
I agree with RVH - It's more challenging finding good enough copies of lenses on the A7RIV than on the A7RIII. More difficult than you would imagine given that the resolution difference isn't very significant - about 20% as I recall.
I know what you mean, but it's not like the lens is any worse on the r4 than on the r3. It's just that you are tempted to examine it at higher magnification: since "1:1" is not the same multiple of the sensor dimensions in a higher resolution camera.
Now, if the reason you bought the higher resolution camera is to make 20% larger prints than the already very large ones you make with your f3, or you have purchased a giant display, maybe your standards for acceptable lenses should go up.
But if that's not the reason: if your final image consuming habits haven't changed, if it was good enough on the r3 it's good enough on the R4 - the extra resolution of the R4 has other benefits (less moire and other demosaising artefacts) beyond increased linear resolution, and the lens doesn't have to be any better to get those benefits.
I agree with RVH - It's more challenging finding good enough copies of lenses on the A7RIV than on the A7RIII. More difficult than you would imagine given that the resolution difference isn't very significant - about 20% as I recall.
I know what you mean, but it's not like the lens is any worse on the r4 than on the r3. It's just that you are tempted to examine it at higher magnification: since "1:1" is not the same multiple of the sensor dimensions in a higher resolution camera.
Now, if the reason you bought the higher resolution camera is to make 20% larger prints than the already very large ones you make with your f3, or you have purchased a giant display, maybe your standards for acceptable lenses should go up.
But if that's not the reason: if your final image consuming habits haven't changed, if it was good enough on the r3 it's good enough on the R4 - the extra resolution of the R4 has other benefits (less moire and other demosaising artefacts) beyond increased linear resolution, and the lens doesn't have to be any better to get those benefits.
Sep 17, 2020 at 08:00 PM
p.16 #15Sony FE 12-24mm f/2.8 GM Review
rvh23 wrote:
I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.No problem! Yes, I am doubtful that the shimming material is that thick. The degree of misalignment looks subtle, less than 50 microns by my very rough estimate. But it also looks decentered, not just tilted or swung, again I'm guessing from your crops. One needs to see the full image and the test subject needs to have certain qualities for one to be absolutely sure.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were grossly asymmetrical. I tried only one and it was too. That's 9 out of 9 all bad, and not slightly bad. Like really bad. I have no idea how anyone gets good copies, surely our luck cannot be this awful. Fred seems to have an amazing copy to kill for. I recall seeing one other great copy on this forum. Joe remembers seeing two others, so we know of a total of 4 copies that are supposedly really great, but we can't seem to find them (I've given up myself, since I don't usually shoot super wide anyways). One would hope the GMs are a little more consistent in that regard, given the cost. Cameras today are too sharp and unforgiving on the optics.
I too remember seeing such statements here from time to time, which has always puzzled me that folks were observing such a phenomenon. Sounded like observational error then.It took me four copies before I had a Sigma 14-24 DG DN that I was happy with, and I thought I was having worse luck than most, but perhaps not judging from your comment.
Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil...Show more →
I'm not sure that I am comfortable with the practice of partially disassembling and then experimentally shimming and altering the plane of focus of multiple lenses that will then be returned to be sold as new to other buyers.
inksandpaper wrote
rvh23 wrote
Thanks very much for all this additional information and taking the time.I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were grossly asymmetrical. I tried only one and it was too. That's 9 out of 9 all bad, and not slightly bad. Like really bad. I have no idea how anyone gets good copies, surely our luck cannot be this awful. Fred seems to have an amazing copy to kill for. I recall seeing one other great copy on this forum. Joe remembers seeing two others, so we know of a total of 4 copies that are supposedly really great, but we can't seem to find them (I've given up myself, since I don't usually shoot super wide anyways). One would hope the GMs are a little more consistent in that regard, given the cost. Cameras today are too sharp and unforgiving on the optics.
Earlier quote
When you say the spacing and allignment shouldn't affect FC, I don't at all doubt your expertise, and even less so the folks at lensrenatals. But my recollection of my adapter shimming days, and also discussion here on FM, is that FC often was affected. But it's possible I'm misremembering the details.Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil...Show more →
I'm not sure that I am comfortable with the practice of partially disassembling and then experimentally shimming and altering the plane of focus of multiple lenses that will then be returned to be sold as new to other buyers.
Sep 17, 2020 at 08:02 PM
p.16 #16Sony FE 12-24mm f/2.8 GM Review
DavidBM wrote:
I know what you mean, but it's not like the lens is any worse on the r4 than on the r3. It's just that you are tempted to examine it at higher magnification: since "1:1" is not the same multiple of the sensor dimensions in a higher resolution camera.
Now, if the reason you bought the higher resolution camera is to make 20% larger prints than the already very large ones you make with your f3, or you have purchased a giant display, maybe your standards for acceptable lenses should go up.
But if that's not the reason: if your final image...Show more →
Totally agree David, especially about your comment on less aliasing on A7R IV images. There is only one point I think we diverge... I think what's acceptable today may not be in the near future. Just speculating, perhaps very soon, it would be very cool to present our images in big 16K displays. Shooting with the R4 instead of R3 would give your detailed landscapes that extra 20% linear resolution -- unfortunatly mostly captured at center. That could be apparent to the most discerning audience but today, it's not visible even on big prints or 5K displays.
Either way, 42 to 61MP is not as significant as 24 to 61. That's an extra 60% linear resolution.
httivals wrote
I agree with RVH - It's more challenging finding good enough copies of lenses on the A7RIV than on the A7RIII. More difficult than you would imagine given that the resolution difference isn't very significant - about 20% as I recall.Now, if the reason you bought the higher resolution camera is to make 20% larger prints than the already very large ones you make with your f3, or you have purchased a giant display, maybe your standards for acceptable lenses should go up.
But if that's not the reason: if your final image...Show more →
Totally agree David, especially about your comment on less aliasing on A7R IV images. There is only one point I think we diverge... I think what's acceptable today may not be in the near future. Just speculating, perhaps very soon, it would be very cool to present our images in big 16K displays. Shooting with the R4 instead of R3 would give your detailed landscapes that extra 20% linear resolution -- unfortunatly mostly captured at center. That could be apparent to the most discerning audience but today, it's not visible even on big prints or 5K displays.
Either way, 42 to 61MP is not as significant as 24 to 61. That's an extra 60% linear resolution.
Sep 17, 2020 at 08:59 PM
p.16 #17Sony FE 12-24mm f/2.8 GM Review
chiron wrote:
I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.No problem! Yes, I am doubtful that the shimming material is that thick. The degree of misalignment looks subtle, less than 50 microns by my very rough estimate. But it also looks decentered, not just tilted or swung, again I'm guessing from your crops. One needs to see the full image and the test subject needs to have certain qualities for one to be absolutely sure.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were grossly asymmetrical. I tried only one and it was too. That's 9 out of 9 all bad, and not slightly bad. Like really bad. I have no idea how anyone gets good copies, surely our luck cannot be this awful. Fred seems to have an amazing copy to kill for. I recall seeing one other great copy on this forum. Joe remembers seeing two others, so we know of a total of 4 copies that are supposedly really great, but we can't seem to find them (I've given up myself, since I don't usually shoot super wide anyways). One would hope the GMs are a little more consistent in that regard, given the cost. Cameras today are too sharp and unforgiving on the optics.
I too remember seeing such statements here from time to time, which has always puzzled me that folks were observing such a phenomenon. Sounded like observational error then.It took me four copies before I had a Sigma 14-24 DG DN that I was happy with, and I thought I was having worse luck than most, but perhaps not judging from your comment.
Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil (so maybe 40um) in the most-adjusted corner. Results showed about the same improvement as for my internal shimming exercise, but the distance readout and FC were not noticeably affected now.
It's now very good at 14mm, not bad at 12mm, but all four corners are softer than I'd like at the long end. My 2nd copy was actually superb at 24mm, but at the wide end had one corner that didn't sharpen up enough even stopped down. So the search continues.
I've pretty much commited to trying as many copies as it takes (hopefully not 10) because this focal range is where I shoot the very large majority of my landscapes.I'm not sure that I am comfortable with the practice of partially disassembling and then experimentally shimming and altering the plane of focus of multiple lenses that will then be returned to be sold as new to other buyers.
I think you misunderstand. In Australia, it's very hard to return a lens to most vendors unless it is obviously faulty. I would never try to return a lens that I have adjusted in any way. For these GMs the only option I have when they are reasonable, but just not to my satisfaction, is to resell them usually at a loss despite having had essentailly no use.
In any case, I only tried adjusting one lens (and returned it to its original condition in the end) and I don't plan to do it with any other copies unless I know for sure I am keeping it and that it is minimally decentered. It's just too much effort.
Edited on Sep 17, 2020 at 09:30 PM · View previous versions
rvh23 wrote
inksandpaper wrote
rvh23 wrote
Thanks very much for all this additional information and taking the time.I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were grossly asymmetrical. I tried only one and it was too. That's 9 out of 9 all bad, and not slightly bad. Like really bad. I have no idea how anyone gets good copies, surely our luck cannot be this awful. Fred seems to have an amazing copy to kill for. I recall seeing one other great copy on this forum. Joe remembers seeing two others, so we know of a total of 4 copies that are supposedly really great, but we can't seem to find them (I've given up myself, since I don't usually shoot super wide anyways). One would hope the GMs are a little more consistent in that regard, given the cost. Cameras today are too sharp and unforgiving on the optics.
Earlier quote
When you say the spacing and allignment shouldn't affect FC, I don't at all doubt your expertise, and even less so the folks at lensrenatals. But my recollection of my adapter shimming days, and also discussion here on FM, is that FC often was affected. But it's possible I'm misremembering the details.Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil (so maybe 40um) in the most-adjusted corner. Results showed about the same improvement as for my internal shimming exercise, but the distance readout and FC were not noticeably affected now.
It's now very good at 14mm, not bad at 12mm, but all four corners are softer than I'd like at the long end. My 2nd copy was actually superb at 24mm, but at the wide end had one corner that didn't sharpen up enough even stopped down. So the search continues.
I've pretty much commited to trying as many copies as it takes (hopefully not 10) because this focal range is where I shoot the very large majority of my landscapes.
I think you misunderstand. In Australia, it's very hard to return a lens to most vendors unless it is obviously faulty. I would never try to return a lens that I have adjusted in any way. For these GMs the only option I have when they are reasonable, but just not to my satisfaction, is to resell them usually at a loss despite having had essentailly no use.
In any case, I only tried adjusting one lens (and returned it to its original condition in the end) and I don't plan to do it with any other copies unless I know for sure I am keeping it and that it is minimally decentered. It's just too much effort.
Edited on Sep 17, 2020 at 09:30 PM · View previous versions
Sep 17, 2020 at 09:04 PM
p.16 #18Sony FE 12-24mm f/2.8 GM Review
rvh23 wrote:
I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.No problem! Yes, I am doubtful that the shimming material is that thick. The degree of misalignment looks subtle, less than 50 microns by my very rough estimate. But it also looks decentered, not just tilted or swung, again I'm guessing from your crops. One needs to see the full image and the test subject needs to have certain qualities for one to be absolutely sure.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were grossly asymmetrical. I tried only one and it was too. That's 9 out of 9 all bad, and not slightly bad. Like really bad. I have no idea how anyone gets good copies, surely our luck cannot be this awful. Fred seems to have an amazing copy to kill for. I recall seeing one other great copy on this forum. Joe remembers seeing two others, so we know of a total of 4 copies that are supposedly really great, but we can't seem to find them (I've given up myself, since I don't usually shoot super wide anyways). One would hope the GMs are a little more consistent in that regard, given the cost. Cameras today are too sharp and unforgiving on the optics.
I too remember seeing such statements here from time to time, which has always puzzled me that folks were observing such a phenomenon. Sounded like observational error then.It took me four copies before I had a Sigma 14-24 DG DN that I was happy with, and I thought I was having worse luck than most, but perhaps not judging from your comment.
Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil (so maybe 40um) in the most-adjusted corner. Results showed about the same improvement as for my internal shimming exercise, but the distance readout and FC were not noticeably affected now.
It's now very good at 14mm, not bad at 12mm, but all four corners are softer than I'd like at the long end. My 2nd copy was actually superb at 24mm, but at the wide end had one corner that didn't sharpen up enough even stopped down. So the search continues.
I've pretty much commited to trying as many copies as it takes (hopefully not 10) because this focal range is where I shoot the very large majority of my landscapes.I'm not sure that I am comfortable with the practice of partially disassembling and then experimentally shimming and altering the plane of focus of multiple lenses that will then be returned to be sold as new to other buyers.I think you misunderstand. In Australia, it's very hard to return a lens to most vendors unless it is obviously faulty. I would never try to return a lens that I have adjusted in any way. For these GMs the only option I have here is to resell copies that are not to my satisfaction, which is usually at a loss despite having had essentailly no use.
In any case, I only tried adjusting one lens (and returned it to its original condition in the end) and I don't plan to do it with any other copies unless I know...Show more →
Good to know. Thank you for clarifying. I am glad to have misunderstood.
chiron wrote
rvh23 wrote
inksandpaper wrote
rvh23 wrote
Thanks very much for all this additional information and taking the time.I don't have a good explanation for the significant distance readout disruption, but there is no way the shimming material is a hundred, let alone several hundred microns thick. The only thing I can think of is that when I punched a hole through it for the screws to pass through it left a burr that acted to increase the effective thickness. But I would expect a shim that is several hundred microns thick and placed in one corner to be way too much adjustment given the lens was not severely asymmetric in the first place.
In relation to the induced FC, no I unfortunately don't have images I can show. It was just an anecdotal observation through the EVF, because by that stage I had already decided I wasn't going to be keeping the lens. But it seemed quite obvious even at 24mm where the lens unshimmed is essentially flat field.
There might be something to say about your long-suffering quest for a great copy. Our experience with the Sigma 14-24 2.8 DG DN was similar. Joe Holmes tried 8 (!) copies and all were grossly asymmetrical. I tried only one and it was too. That's 9 out of 9 all bad, and not slightly bad. Like really bad. I have no idea how anyone gets good copies, surely our luck cannot be this awful. Fred seems to have an amazing copy to kill for. I recall seeing one other great copy on this forum. Joe remembers seeing two others, so we know of a total of 4 copies that are supposedly really great, but we can't seem to find them (I've given up myself, since I don't usually shoot super wide anyways). One would hope the GMs are a little more consistent in that regard, given the cost. Cameras today are too sharp and unforgiving on the optics.
Earlier quote
When you say the spacing and allignment shouldn't affect FC, I don't at all doubt your expertise, and even less so the folks at lensrenatals. But my recollection of my adapter shimming days, and also discussion here on FM, is that FC often was affected. But it's possible I'm misremembering the details.Increasingly, from reading your posts, I'm thinking something must have gone wrong with my internal shim on the GM. Since I was waiting for copy #4, this afternoon I went back and tried mounting shims on the camera's lens mount instead where it's easier to be sure the shims are flat and don't need holes. This time it took about 4 layers of the foil (so maybe 40um) in the most-adjusted corner. Results showed about the same improvement as for my internal shimming exercise, but the distance readout and FC were not noticeably affected now.
It's now very good at 14mm, not bad at 12mm, but all four corners are softer than I'd like at the long end. My 2nd copy was actually superb at 24mm, but at the wide end had one corner that didn't sharpen up enough even stopped down. So the search continues.
I've pretty much commited to trying as many copies as it takes (hopefully not 10) because this focal range is where I shoot the very large majority of my landscapes.
In any case, I only tried adjusting one lens (and returned it to its original condition in the end) and I don't plan to do it with any other copies unless I know...Show more →
Good to know. Thank you for clarifying. I am glad to have misunderstood.
Sep 17, 2020 at 09:28 PM
p.16 #19Sony FE 12-24mm f/2.8 GM Review
DavidBM wrote:
Now, if the reason you bought the higher resolution camera is to make 20% larger prints than the already very large ones you make with your f3, or you have purchased a giant display, maybe your standards for acceptable lenses should go up.
Or if you are wanting to print the same size prints at 20% higher resolution, which was the case for me.
Now, if the reason you bought the higher resolution camera is to make 20% larger prints than the already very large ones you make with your f3, or you have purchased a giant display, maybe your standards for acceptable lenses should go up.
Or if you are wanting to print the same size prints at 20% higher resolution, which was the case for me.
Sep 17, 2020 at 09:48 PM
p.16 #20Sony FE 12-24mm f/2.8 GM Review
rvh23 wrote:
Or if you are wanting to print the same size prints at 20% higher resolution, which was the case for me.
Fair enough, but it would need to be a very large print for the extra linear resolution to be visible, which was my point.
DavidBM wrote
Now, if the reason you bought the higher resolution camera is to make 20% larger prints than the already very large ones you make with your f3, or you have purchased a giant display, maybe your standards for acceptable lenses should go up.Fair enough, but it would need to be a very large print for the extra linear resolution to be visible, which was my point.
Sep 17, 2020 at 09:57 PM