p.4 #1 · Issue with the Sony Zeiss 55/1.8 FE or A7
wayne seltzer wrote:
Jochen, this lens looks to have strong field curvature at distance like the zf 25/2.8.
If I remember right from when I had Diglloyd subscription, he showed how the FC changed depending on subject/focus point distance from camera and aperture.
On top of that there seems to be decentering or mount problem causing difference in sides like you see. Maybe the strong FC of this lens amplifies the decentering or mount problem where the two sides are different. How does a different lens perform on this camera at these distances?
Any difference in sides?
A different lens on this camera doesn't behave like my 55/1.8. I don't get the strange differences between left and right. What I do get is much stronger field curvature (this time symmetrical) than when I used that same lens on a DSLR. So another unpleasant "feature" of the A7.
The store agreed with me sending it all back for a refund so that's what I'm going to do. I'm done for now with all these compromises. When I shoot with my RX1 I feel that there are no compromises when it comes to IQ, that's a totally different feeling than with the A7.
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*edit: I need to correct something: with the other lens I also noticed a weaker left side after all. So the final conclusion is that it might have been a faulty camera.
p.4 #2 · Issue with the Sony Zeiss 55/1.8 FE or A7
Sorry to hear about all the problems. So it sounds like you had a bad camera which was causing the difference between sides but that this 55/1.8 lens also has strong FC, right which is too bad since it performs well close up.
p.4 #3 · Issue with the Sony Zeiss 55/1.8 FE or A7
Just got my 55mm FE from B&H. Using it on A7R
Exhibits same issue: i.e. Right side is perfect. Left side is not so.. but it's not as bad as samples here. Also noticed same weird angle of focus coming towards the camera from right to left. I'll have to do some more strict tests.
Would like to know from those with this lens if theirs is pretty much perfect or with slight variations...before I return mine....Humm I wonder if I got a lens that was ret'd by someone else for same issue? or if a lot of them have same/similar issues?
p.4 #4 · Issue with the Sony Zeiss 55/1.8 FE or A7
Just sounds like a decentered or tilted element. Send it back and get a second one. All manufacturers make lemons from time to time. Hopefully yours isn't the camera plane like jochen's was.
p.4 #6 · Issue with the Sony Zeiss 55/1.8 FE or A7
A quick (and possibly dirty) test would be with two reasonably fast lenses. Point camera out over an even homogenous motif such as a grass lawn. The lawn should be evenly lit and preferably full of contrast. Set focus peaking to its limit, set lens#1 wideopen and move focus ring back and forth. Is the peaking pattern horisontal? Then no signs of issue. If not horisontal there could be an issue with lens or sensor. Repeat with lens#2 to decide wether its a decentered lens or sensor.
Now, this may not be very scientific but it could be an easy way to lay rest upon a suspicious mind.
p.4 #7 · Issue with the Sony Zeiss 55/1.8 FE or A7
I just purchased an A7R with 55 FE and 35 FE and also noticed the left side of the image to be soft while the centre and right are sharp.
Because it's happening on both lenses I believe it to be a case of tilting rather than decentering.
I live on the top floor of an apartment building and have a clear view to the horizon. I shot a series of images with both lenses, moving the focus from its minimum to infinity. The plane of focus should have moved out parallel to the sensor to the horizon. What I got however was an almost parallel plane of focus at close distance which tilted to a plane of focus at 45 degrees to the sensor.
I had a look at the mount on the A7R and it appears as if it's not parallel to the sensor. On the left side there is a 1mm gap between the lens barrel and the mount, whereas on the right it looks more like 1.2mm. This would also confirm my theory that it's tilt. There are 4 screws on the mount and hopefully adjusting these may change the angle of the mount to the sensor. If so, it's a simple calibration issue. I might however try the lenses on another A7R body before I start making physical changes to my camera.
As far as the lens flare, I tested an A7 against an A7R and found more lens flare on the A7. I purchased a Hasselblad H3D some time ago and got such bad flare that even my clients noticed. After a bit of legal wrangling the dealer swapped it for the upgraded model which had just been released and which funnily enough had an updated IR filter. As expected, the H3DII was flare free. I believe the flare is caused by reflections WITHIN the IR filter mounted on top of the sensor. It explains why the flare is often green (because the IR filter removes red wavelengths). Even $20,000 professional medium format backs aren't perfect! It might be possible that the micro lenses on the A7R might change the nature of reflections.
p.4 #8 · Issue with the Sony Zeiss 55/1.8 FE or A7
I have never tested the performance of my FE55 until now, but two weeks ago I noticed that infinity shots at the wider aperture were noticeably unsharp on the left side. Some testing shows that the plane of focus is tilted, focused at infinity the image is in focus at about 20m on the left side while it is sharp at infinity in the centre and right side. (My FE 35 is fine.)
Sending it off for adjustment/ replacement, hoping Sonys turnaround is faster now than when my RX1 was serviced.
p.4 #9 · Issue with the Sony Zeiss 55/1.8 FE or A7
I'm sorry to hear that Twoeye! Hopefully you'll have it back soon (and fixed).
To update this thread:
A few months after I started this thread I decided to try another A7 with FE55. No issues. Maybe my first A7 had a slightly tilted mount or many FE55 lenses have the exact same issue.
p.4 #10 · Issue with the Sony Zeiss 55/1.8 FE or A7
I'm glad this thread existed prior to purchasing mine. The first copy I tried had exactly the same issue with the left side of the frame. The second copy is just about perfect based on my testing, still haven't gone through more extensive images I shot while recently travelling though.
p.4 #11 · Issue with the Sony Zeiss 55/1.8 FE or A7
twoeye wrote:
I have never tested the performance of my FE55 until now, but two weeks ago I noticed that infinity shots at the wider aperture were noticeably unsharp on the left side. Some testing shows that the plane of focus is tilted, focused at infinity the image is in focus at about 20m on the left side while it is sharp at infinity in the centre and right side. (My FE 35 is fine.)
Sending it off for adjustment/ replacement, hoping Sonys turnaround is faster now than when my RX1 was serviced.
Short update: My FE 55 was replaced by a second copy which had the exact same issue, it is going back for replacement again. No other lenses shows this tilted plane of focus on my A7r.
p.4 #12 · Issue with the Sony Zeiss 55/1.8 FE or A7
twoeye wrote:
Short update: My FE 55 was replaced by a second copy which had the exact same issue, it is going back for replacement again. No other lenses shows this tilted plane of focus on my A7r.
p.4 #16 · Issue with the Sony Zeiss 55/1.8 FE or A7
carstenw wrote:
What's weird? It looks like a plane which is in focus which slices the lens in half.
carsten that is what I thought as well. However I don't think both 'in focus' points are in the same plane.
p.4 #17 · Issue with the Sony Zeiss 55/1.8 FE or A7
I heard that there is a problem with the lens mount on the A7 that it is plastic and people have had problems. Someone make a metal replacement for it. Check to see if the lens show any signs of flexing between the camera body and the lens. This could be your problem.
p.4 #18 · Issue with the Sony Zeiss 55/1.8 FE or A7
prashant, I think they are. If you look, not at the sharp letters on the side, but at the front-most part on the left side which is in focus, somewhere up the focus ring, then that corresponds with the front of the filter ring, which just happens to sit at the very front of the focus plane/slice.
p.4 #19 · Issue with the Sony Zeiss 55/1.8 FE or A7
Theron, there is flex behind the mount somewhere, but the mount is apparently rigidly attached to the sensor cage, and only loosely to the body itself, so it normally shouldn't be a problem. The actual problem with this mount is not the plastic ring, but the weak springs in the mount, AFAIK. In either case, I presume the Fotodiox mount also improves on the springs, so it might be worth getting in any case.
Oct 26, 2014 at 06:30 PM
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p.4 #20 · Issue with the Sony Zeiss 55/1.8 FE or A7
My first FE55 was decentered (same as reported here with left side unsharp at infinity due to being focused closer). Exactly the same problem was with FE35, but even more pronounced.
I went to a local Sony service and had my camera (A7r) checked and sensor/mount assembly replaced + they gave me new lenses. The new FE35 is fine, but the new FE55 is still decentered, albeit less than my previous sample. It's now at least possible to hide the defect at infinity by stopping down to f5.6-f8 and focusing precisely using LV.
I'll replace my FE55 again when I have time. It's very annoying and it looks like Sony has pretty bad quality control. Since the defect in FE55 is always the same (focus plane skew) it could be a specific problem at the assembly line. I think I'll wait till the next summer before asking for a replacement to give Sony as much time as I can to fix the problem.
It seems the only lenses with consistent quality are Zeiss ZF/ZE (defects are rare) and obviously Otus (all lenses appear to be perfect)
