p.4 #1 · Sensor and lens tilt and how to DIY adjust your equipment
Fred Miranda wrote:
Wouldn't 0.005 (5 microns) be enough? I mean, it would be already hard to spot a 5-micron skew, why would I need 1 micron (0.001)?
What do you mean by leaf spring?
I will re-read your article to see how to deal with adapter wobble.
Thanks for your insight.
Fred
Oh that's because the units are in inches not mm from McMaster-Carr, US company dealing in imperial units.
I shared your mount picture with Joe and he astutely pointed out what looks like weather sealing gasket going around the outer edge. There may not be enough space to squeeze a 4mm OD shim in there. Maybe only 3mm will fit. Tight!
There are 'leaf' or lever style springs, you can see three separate tabs/pieces in your photo (it's a single ring on the a7r II), which create the necessary tension to hold the camera and lens bayonet faces tight to each other. They are the shiny flaps of metal between the screw holes.
You just need to take note of the orientation of the 360 rotating rear end for the 4-camera-flipping positions. Measure off the point where you choose to evaluate the test images. E.g. I look at the left image edge. So I measure at the right edge on the adapter. That is, the adapter's rear is facing me, I'm measuring the 3 o'clock position. Then operate the adapter's rear rotating mechanism to rotate the rear end 180 degrees and measure the same spot again. The difference is the amount of wobble caused by the rotating rear end in the swing/horizontal direction. Do that again for tilt. You'll need to translate that to what's happening at the sensor by working out the ratio between the measurement points on the adapter (which is just its diameter) to the width and height of the sensor. That is the 'wobble' error that the adapter is contributing. Hope it helps!
p.4 #2 · Sensor and lens tilt and how to DIY adjust your equipment
This great all this info on here and in your article. I have a Mirex Sony E to Canon EF I got last year. I’ll be interested to test my Sony A7R2 and A7R3.
I was shimming Metabones adapters for my Canon 17TSE and 24TSE II many years ago. The fully shifted corners couldn’t hit infinity focus till I hand shimmed them. I’d like to revisit this with your round shims and look at some of my other lenses. My old shimming was to cut out templates from 0.005mm and 0.01mm flat stainless steel.
p.4 #3 · Sensor and lens tilt and how to DIY adjust your equipment
TakenWild wrote:
This great all this info on here and in your article. I have a Mirex Sony E to Canon EF I got last year. I’ll be interested to test my Sony A7R2 and A7R3.
I was shimming Metabones adapters for my Canon 17TSE and 24TSE II many years ago. The fully shifted corners couldn’t hit infinity focus till I hand shimmed them. I’d like to revisit this with your round shims and look at some of my other lenses. My old shimming was to cut out templates from 0.005mm and 0.01mm flat stainless steel.
Hi TakenWild, glad you are finding the information useful. I didn't know about stainless steel foils that are only 5 microns thick. Do you mind sharing your source for that? I can't imagine how difficult it is to work with 5-micron foils, but I have wished I had that from time to time. 10-microns is already incredibly fragile stuff!
p.4 #4 · Sensor and lens tilt and how to DIY adjust your equipment
Sorry got my measurements wrong, I used, 50 microns and 100 microns, not 5 and 10. I think I’d like to try lower to get more precise.
inksandpaper wrote:
Hi TakenWild, glad you are finding the information useful. I didn't know about stainless steel foils that are only 5 microns thick. Do you mind sharing your source for that? I can't imagine how difficult it is to work with 5-micron foils, but I have wished I had that from time to time. 10-microns is already incredibly fragile stuff!
p.4 #5 · Sensor and lens tilt and how to DIY adjust your equipment
Fred Miranda wrote:
BTW: For those who want to test the camera mount/sensor parallelism (as posted by Samuel on his article), there is a Kipon shift adapter (EF to E) that has a tripod mount and rotates 360 degrees. This is an alternative to the Mirex since it's discontinued:
Fred and to anyone who might be purchasing Kipon adapters: I've been seeing today several user reports and reviews of light leak with their adapters and poor machining of both the lens side and camera side bayonets. Someone even got a lens stuck, apparently. Be careful when you are mounting this adapter the first time to your precious equipment, lest you damage them. Good luck! Hope you get a good one. We lost a lot with Markus going out of business making the Mirex adapters. :'(
p.4 #6 · Sensor and lens tilt and how to DIY adjust your equipment
inksandpaper wrote:
Oh that's because the units are in inches not mm from McMaster-Carr, US company dealing in imperial units.
I shared your mount picture with Joe and he astutely pointed out what looks like weather sealing gasket going around the outer edge. There may not be enough space to squeeze a 4mm OD shim in there. Maybe only 3mm will fit. Tight!
There are 'leaf' or lever style springs, you can see three separate tabs/pieces in your photo (it's a single ring on the a7r II), which create the necessary tension to hold the camera and lens bayonet faces tight to each other. They are the shiny flaps of metal between the screw holes.
You just need to take note of the orientation of the 360 rotating rear end for the 4-camera-flipping positions. Measure off the point where you choose to evaluate the test images. E.g. I look at the left image edge. So I measure at the right edge on the adapter. That is, the adapter's rear is facing me, I'm measuring the 3 o'clock position. Then operate the adapter's rear rotating mechanism to rotate the rear end 180 degrees and measure the same spot again. The difference is the amount of wobble caused by the rotating rear end in the swing/horizontal direction. Do that again for tilt. You'll need to translate that to what's happening at the sensor by working out the ratio between the measurement points on the adapter (which is just its diameter) to the width and height of the sensor. That is the 'wobble' error that the adapter is contributing. Hope it helps!...Show more →
Makes sense now! Thanks for the info.
I will first try with the 4mm and if it does not fit, I will order the 3mm outer diameter.
If it intersects with the leaf spring, should it go under or above it?
Thanks for the info on the wobble. I will definitely keep an eye for it.
p.4 #7 · Sensor and lens tilt and how to DIY adjust your equipment
inksandpaper wrote:
Fred and to anyone who might be purchasing Kipon adapters: I've been seeing today several user reports and reviews of light leak with their adapters and poor machining of both the lens side and camera side bayonets. Someone even got a lens stuck, apparently. Be careful when you are mounting this adapter the first time to your precious equipment, lest you damage them. Good luck! Hope you get a good one. We lost a lot with Markus going out of business making the Mirex adapters. :'(
I'm surprised by this since Kipon usually makes good adapters. Hopefully I will get one up to specs.
p.4 #8 · Sensor and lens tilt and how to DIY adjust your equipment
Fred Miranda wrote:
Makes sense now! Thanks for the info.
I will first try with the 4mm and if it does not fit, I will order the 3mm outer diameter.
If it intersects with the leaf spring, should it go under or above it?
Thanks for the info on the wobble. I will definitely keep an eye for it.
No problem! It should overlap on top of the leaf spring in that case. Best to avoid touching the weather sealing gasket so as not to compromise its function.
p.4 #9 · Sensor and lens tilt and how to DIY adjust your equipment
inksandpaper wrote:
No problem! It should overlap on top of the leaf spring in that case. Best to avoid touching the weather sealing gasket so as not to compromise its function.
I got this today from the Kipon Shift adapter seller:
"Unfortunately i‘ve got the notify from the courier today. they said your package was returned back. because they can‘t ship parcels to your country currently. i don‘t know why because currently there is not so many affect by Covid-19 in shipment."
They cancelled my order! Seems really weird as nothing changed regarding Covid and shipments from China to the US. I need to find another source now.
p.4 #11 · Sensor and lens tilt and how to DIY adjust your equipment
TakenWild wrote:
Since you are just using these adapter for testing try Fotodiox shift adapter. It wasn’t great quality, but it will be fine for testing.
As far as I can tell, it does not have a tripod mount and this is crucial for this type of test since the camera is the one that rotates, not the lens.
p.4 #15 · Sensor and lens tilt and how to DIY adjust your equipment
Fred Miranda wrote:
As far as I can tell, it does not have a tripod mount and this is crucial for this type of test since the camera is the one that rotates, not the lens.
Fred, sorry to hear that the Kipon adapter will not be shipped to you at this time. Anyway, it's also OK if the lens is flipped relative to the camera, you just have to pan the camera in the yaw direction to reposition the test subject to the opposite side of the frame. It just adds another flipping inversion to the orientation when you're trying to figure out the lens extension position on the sensor.
p.4 #16 · Sensor and lens tilt and how to DIY adjust your equipment
inksandpaper wrote:
Fred, sorry to hear that the Kipon adapter will not be shipped to you at this time. Anyway, it's also OK if the lens is flipped relative to the camera, you just have to pan the camera in the yaw direction to reposition the test subject to the opposite side of the frame. It just adds another flipping inversion to the orientation when you're trying to figure out the lens extension position on the sensor.
Not sure exactly which component you are referring to? Any good adapter will work, assuming you have the lens for it. The tripod mount looks like it would be helpful, sure. I was just pointing out that the technique can be adapted slightly and still works if the lens is flipped relative to the camera instead. You still need an adapter which has a 360-degree rotating rear end. Otherwise I would have recommended that Canon/Nikon TS-E lenses can be used, since they also have rotating rear ends, but, you can't measure the wobble of those! So any conclusions drawn with TS-E lenses have to be defenestrated.
p.4 #18 · Sensor and lens tilt and how to DIY adjust your equipment
inksandpaper wrote:
Not sure exactly which component you are referring to? Any good adapter will work, assuming you have the lens for it. The tripod mount looks like it would be helpful, sure. I was just pointing out that the technique can be adapted slightly and still works if the lens is flipped relative to the camera instead. You still need an adapter which has a 360-degree rotating rear end. Otherwise I would have recommended that Canon/Nikon TS-E lenses can be used, since they also have rotating rear ends, but, you can't measure the wobble of those! So any conclusions drawn with TS-E lenses have to be defenestrated....Show more →
Sorry that was not clear, typing on the phone. I meant, do you think the Fotodiox and Contax 100-300 would be a good set-up for this?
Also, if I understood this correctly, it does not matter if we are rotating the lens relative to camera or camera relative to lens as long as we are examining each edge of the sensor for focus plane shift.
p.4 #19 · Sensor and lens tilt and how to DIY adjust your equipment
Fred Miranda wrote:
Sorry that was not clear, typing on the phone. I meant, do you think the Fotodiox and Contax 100-300 would be a good set-up for this?
Also, if I understood this correctly, it does not matter if we are rotating the lens relative to camera or camera relative to lens as long as we are examining each edge of the sensor for focus plane shift.
I'm not 100% sure (because I dont have the same parts to try) but I'm pretty sure it should work well. Assuming the adapter indeed behaves as described. I trust the Contax is sharp enough wide open for you to visually identify the true center of the plane of focus very precisely. Observing the blur gradient of the near edge of the depth of field is necessary to be certain. If its sharp in the corners doesn't mean the camera is straight. Offhand without calculations, the depth of focus at f/4.5 to 5.6 is over 30 microns, possibly over 50. This is way harder to see than one could ever expect, for those attempting this the first time.
It does matter in that you have to pan the camera over if you are flipping the lens to put the test subject on the opposite side of the frame. Otherwise you're not eliminating the error introduced by the lens's optics.
