alundeb wrote:
How is the MTF of the A 300 / 2.8 APO wide open compared to the Canon 300 mm 2.8 IS mark I ? The magnitude of the diffrenece is only interesting to me either on high pixel density cameras like the D800 or NEX7, or with the best there is of 2x teleconverters.
I can't answer most of your comparison questions, but I can handle this one in subjective terms.
The Mamiya 645 A 300/2.8 APO is every bit as sharp all across the frame as the EF 300/2.8L IS, on a 1DsIII. I'd still have the 300 APO if not for a mishap during servicing.
Of course, it's much easier to get sharp images out of the EF 300/2.8L IS, given its AF and IS, but the 300 APO is "just as good", given proper technique.
The only objective evidence I can easily find is the following resolution tests I did a few years ago with the 1DsIII, using the USAF 1951 resolution test target. The first table shows calculated resolution in Lines per millimetre (lpmm) for the centre at f/min, f/4 and f/8, and the second table shows similar data for the corner of the frame.
sflxn wrote:
What exactly in this photo do you want to replicate? I'm not sure I see anything there that cannot be replicated with a FF lens.
Then you have some serious problems with your eyesight. Good luck finding a lens with the same sharpness and local contrast at that DOF on FF.
I won't discuss this any further. Buy whatever you want and believe whatever you want. I guess it's like with religious people; they are not interested in facts or truth, because they "know" already.
Makten wrote:
What are the best native APS-C alternatives that you compare with?
The native lenses I've tried is the kit zoom, the 50 f1.8 and the two sigmas, none of which I'm ever again mounting on my camera. There's no native ~100 macro to compare, nor is there a native 80-110 portrait lense, so in that regard there is no direct comparison,
I have however compared the 645 format Contax macro to all my 35mm format macros (which by your reasoning should be better on NEX), and concluded that the MF lens is as good or better (as sharp or sharper) than all the 35mm lenses I tested. Among them the Bokina, makro-planar, makro-sonnar and s-planar 100.
Martin, that last bit of detail contrast is indeed VERY hard to see in the magnification you showed here. At image sizes close to what the APS or FF format outputs today (16-24MP) the difference is plainly visible - but in the small sample I would actually say that main thing indicating a larger format is the extremely smooth through-focus transition.
Makten wrote:
Then you have some serious problems with your eyesight. Good luck finding a lens with the same sharpness and local contrast at that DOF on FF.
I won't discuss this any further. Buy whatever you want and believe whatever you want. I guess it's like with religious people; they are not interested in facts or truth, because they "know" already.
Woah there, I just asked a simple question and you went all crazy. There is a saying we used to say in America, "take a chill pill." Go get some stress relief. I was asking a simple question. I didn't come into this thread to discuss lenses since the OP asked about digital backs. It was the first question I asked on this thread about lens. From your response, I can tell you are stressed out. Go take a walk.
As for that image. I don't know. Maybe it's the subject matter that's making it hard for me to see what characteristic couldn't be duplicated with an 85/1.4, 85/1.2, or comparable Zeiss.
alundeb wrote:
How is the MTF of the A 300 / 2.8 APO wide open compared to the Canon 300 mm 2.8 IS mark I ? The magnitude of the diffrenece is only interesting to me either on high pixel density cameras like the D800 or NEX7, or with the best there is of 2x teleconverters.
jcolwell wrote:
I can't answer most of your comparison questions, but I can handle this one in subjective terms.
The Mamiya 645 A 300/2.8 APO is every bit as sharp all across the frame as the EF 300/2.8L IS, on a 1DsIII. I'd still have the 300 APO if not for a mishap during servicing.
Of course, it's much easier to get sharp images out of the EF 300/2.8L IS, given its AF and IS, but the 300 APO is "just as good", given proper technique.
The only objective evidence I can easily find is the following resolution tests I did a few years ago with the 1DsIII, using the USAF 1951 resolution test target. The first table shows calculated resolution in Lines per millimetre (lpmm) for the centre at f/min, f/4 and f/8, and the second table shows similar data for the corner of the frame. ...Show more →
Thank you, it is at least some comparative information.
When you get the same numbers for the Planar 85 at f/4 and f/8, that tells me something about the accuracy and error margin of your data. With high quality lenses, there is usually about 5% drop in resolution from f/4 to f/8 due to diffraction. For example, photozone get numbers like that, and I can also see it in my images with the D800E.
For the Rokinon, getting the same numbers at f/1.4 and f/4 indicates an even larger error margin, about 10%
These differences are like between the EF 100mm f/2 and the EF 135 mm f/2 L. So when you say the A300/2.8 APO is every bit as sharp as the EF 300 2.8 L IS, it is like hearing it from someone who says that the EF 100/2 is every bit as sharp as the EF135/2 L.
Not that it is bad. I can extract that the difference between these lenses is probably lesss than ...
alundeb wrote:
How is the APO correction of the A 150 / 2.8 compared to the Sigma 150 2.8 APO macro OS?
How is the center MTF of the A 150 / 2.8 compared to the Sigma 150 2.8 APO macro OS, wide open aperture, at long distances?
RustyBug wrote:
These are very fair questions.
I don't have anything to offer in the form of A/B comparison shots or test data, but I can tell you that I rented the Sigma a few years ago and it was a fine enough lens, but I wasn't compelled to buy one as I already owned the Mamiya 150/2.8 A (which I paid a whopping $150 for). Of course, mine is not AF, which you can get @ B&H for $3,490, if you prefer. http://www.bhphotovideo.com/bnh/controller/home?O=&sku=567935&is=REG&A=details&Q=
Thank you, I appreciate the information. My perspective is that I already got the Sigma with full functionality, an outstanding lens at a reasonable cost for what you get. It has a bit lower contrast wide open than stopped down. I still haven't got any information telling me that the that the Mamiya actually will be an improvement. Maybe I have to try it myself.
Regarding the theoretical part of the discussion, it's always important to give the comparison criteria BEFORE making any kind of definitive statements.
In the MTF comparison between the Zeiss100/2 and the Mam120/4 one should remember to state if you're comparing on the SAME format, or on two different formats.
*Each format has its' own lp/mm to image resolution relationship.
This is why Olympus give MTF for their µFT lenses in 20/60 lp/mm when the industry standard is 10/30. To enable a usable comparison. If the µFT camera NEEDS an MTF of 50 at 60lp/mm to give the image a certain sharpness, the FF camera alternative needs only reach that MTF at 30lp/mm to give the SAME end image sharpness.
The only "straight" comparison I've done that's close to perfect in relationship is FF+150/2.8A, FF+Sig150/2.8 and the Zeiss 100/2 mounted on APS. In that comparison, the Zeiss needs to be AT LEAST as sharp at 45lp/mm as the other two are at 30lp/mm if the images are to be similar in sharpness. Lets just shortly say that "it isn't". Not even close - and the LoCA is about 2-4x stronger when the magnification factor is added in to the real comparison.
And regarding that - the Sigma 150 (both OS and older non-OS versions) have less OOF LoCA (bokeh fringes) than the 150/2.8A. I'm not entirely sure about the in-focus LoCA per the strict definition.
theSuede wrote:
Regarding the theoretical part of the discussion, it's always important to give the comparison criteria BEFORE making any kind of definitive statements.
In the MTF comparison between the Zeiss100/2 and the Mam120/4 one should remember to state if you're comparing on the SAME format, or on two different formats.
*Each format has its' own lp/mm to image resolution relationship.
This is why Olympus give MTF for their µFT lenses in 20/60 lp/mm when the industry standard is 10/30. To enable a usable comparison. If the µFT camera NEEDS an MTF of 50 at 60lp/mm to give the image a certain sharpness, the FF camera alternative needs only reach that MTF at 30lp/mm to give the SAME end image sharpness.
The only "straight" comparison I've done that's close to perfect in relationship is FF+150/2.8A, FF+Sig150/2.8 and the Zeiss 100/2 mounted on APS. In that comparison, the Zeiss needs to be AT LEAST as sharp at 45lp/mm as the other two are at 30lp/mm if the images are to be similar in sharpness. Lets just shortly say that "it isn't". Not even close - and the LoCA is about 2-4x stronger when the magnification factor is added in to the real comparison.
And regarding that - the Sigma 150 (both OS and older non-OS versions) have less OOF LoCA (bokeh fringes) than the 150/2.8A. I'm not entirely sure about the in-focus LoCA per the strict definition....Show more →
I thought it was pretty clear that the MTF discussion on the last few pages ("The Myth") has been in the context all lenses used on the same sensor.
And DO NOT make the mistake to bundle the Mam 150/2.8A together with the newer AF version!
The old faithful A version is indeed very, very good. One of my favorite medium telephotos. But it isn't really close to the newer 150AF2.8. I'd classify the AF version as better than the HC150/3.2 (though the only two samples I've tried were most probably / hopefully less than 100% in performance), better than the Sigma150 (just as sharp or sharper, less vignette and more field uniformity), better than the Leica S180 MF (better CA corrections, better sharpness).
alundeb wrote:
I thought it was pretty clear that the MTF discussion on the last few pages ("The Myth") has been in the context all lenses used on the same sensor.
Yes, but the ORIGINAL thread is about MF lenses on MF cameras....
Thread title: "Yesterday's medium format digital backs"
Just to put some more differential between the parallel "MF lens on MF" and "MF lens on FF" discussions.
theSuede wrote:
And DO NOT make the mistake to bundle the Mam 150/2.8A together with the newer AF version!
The old faithful A version is indeed very, very good. One of my favorite medium telephotos. But it isn't really close to the newer 150AF2.8. I'd classify the AF version as better than the HC150/3.2 (though the only two samples I've tried were most probably / hopefully less than 100% in performance), better than the Sigma150 (just as sharp or sharper, less vignette and more field uniformity), better than the Leica S180 MF (better CA corrections, better sharpness).
alundeb wrote:
Thank you, it is at least some comparative information.
When you get the same numbers for the Planar 85 at f/4 and f/8, that tells me something about the accuracy and error margin of your data....
Actually, it's limited by the maximum resolution of the 1DsIII sensor. The next highest resolution above 71~72 lpmm (based on USAF 1951 line pairs), exceeds the 1DsIII theoretical resolution of 78 lpmm. Values below that are consistent and representative of performance. Each condition was tested three times, and results are generally very consistent. Of course, this is for only one sample of each lens.
alundeb wrote:
... So when you say the A300/2.8 APO is every bit as sharp as the EF 300 2.8 L IS, it is like hearing it from someone who says that the EF 100/2 is every bit as sharp as the EF135/2 L.
theSuede wrote:
Martin, that last bit of detail contrast is indeed VERY hard to see in the magnification you showed here. At image sizes close to what the APS or FF format outputs today (16-24MP) the difference is plainly visible - but in the small sample I would actually say that main thing indicating a larger format is the extremely smooth through-focus transition.
I'm not talking about resolution, but about "look". You don't get this look from a fast normal on FF and I have a hard time understanding anyone with the least experience in photography who cannot see that even at small sizes.
alundeb wrote:
... So when you say the A300/2.8 APO is every bit as sharp as the EF 300 2.8 L IS, it is like hearing it from someone who says that the EF 100/2 is every bit as sharp as the EF135/2 L.
jcolwell wrote:
Now that's patronizing. I can take a hint.
Ok, it was maybe a bit harsh of me. Apologies for that. Let me rather say that since the resolution data hit the ceiling on the sensor they were measured on, and I use higher resolution sensors where I can see differences your method doesn't pick up, the data are not what I am looking for. My context is lenses for my dual D800 and NEX 7 setup, and how a 300 2.8 lens performs as a 600 5.6 lens on those.
briantho wrote:
I guess it's sort of like seeing the "3D-look"?
No, more like seeing that there is no visible purple fringing, spherial aberration haze, extreme vignetting, terrible corner bokeh, severe LCA and other things that would show up with a fast enough 50 mm lens on FF to give the same DOF and/or background blur at that particular distance.
Are you aware of the difference between APS-C and FF? Or between FF and MTF? Then you should be aware of the difference between MF and FF, which in this case (6x7) is very visible.
Makten wrote:
No, more like seeing that there is no visible purple fringing, spherial aberration haze, extreme vignetting, terrible corner bokeh, severe LCA and other things that would show up with a fast enough 50 mm lens on FF to give the same DOF and/or background blur at that particular distance.
Are you aware of the difference between APS-C and FF? Or between FF and MTF? Then you should be aware of the difference between MF and FF, which in this case (6x7) is very visible.
You have been nothing but rude to quite a few people in this thread. A few pages back you lashed out at rusty for no apparent reason...
There is people like me who are indeed trying to learn and have an enjoyable read... I'm not really sure if you are just mad at life or who knows... But please.... Don't bring it here..
All respectfully and kindly... Keep it constructive..
Nah, think Makten got carried away because I didn't read enough into the change in discussion line from "sharpness" to "rendering".
The image he showed does indeed show a "kind" of field uniformity that's all but non-existent in fast wider-than-60mm FF lenses. Though I guess the new ZF2-55/1.4 could change that.
If you're an avid medium-short shooter, then a D800 and that Zeiss lens might actually save you a lot of money. I know what developing and printing/scanning from MF film costs.... Especially if you want to run a few thousand frames per year.
