Subtle decentering in the Sony Zeiss 55mm f/1.8

[dllu]

After owning it for about one and a half months, I noticed some decentering in my Sony Zeiss 55mm f/1.8, causing the left edge to be soft.

 

Example 1: https://upload.wikimedia.org/wikipedia/commons/e/ea/Paradise_visitor_center.jpg (at f/4: the car license plate in the bottom left is strangely sharp when the park ranger in the middle is not; and also compare the faraway trees on the left with the trees on the right).

 

Example 2: https://upload.wikimedia.org/wikipedia/commons/0/0b/Capitolhill_panorama_1_frame_6.JPG (at f/2.8: the bottom of the brick and glass condominium is extremely soft whereas the top is acceptably sharp, even though the whole building is far away and should be coplanar with the plane of focus)

 

Example 3: http://daniellawrencelu.com/2097d24a975eb4d96f1b375cc2821997891ad88b/ce772f11a166ab7e5fae57f8e7540cd2ece214c7__DSC02135.jpg (even at f/7.1 the left edge is noticeably less sharp than the rest of the picture)

 

But the issue is not nearly as pronounced as some of the people on: http://www.fredmiranda.com/forum/topic/1276896

 

Should I try to send it to Sony to get repaired under warranty? Also, from the fredmiranda forum, apparently Sony only tests the lens on the APS-C camera a6000 which would not detect this flaw.

[christer]

I think your pictures can not be used to seriously judge whether the lens is decentered or not. For that you have to mount the lens on a tripod and photograph a flat surface that is absolutely parallel to the sensor plane.

[Golem]

Cannot get examples 2 and 3 to load, but no problem.

Given the "symptoms" you say you see in example 1,

I'd say fergeddaboudit. All the image flaws you point

out have waaaay too many other, more likely, causes.

 

`

[Golem]

OK, got example 2 to load.

 

While as a diagnostic tool the shot

is hardly useful, you could far more

easily see curvature of field instead

of decentering.

 

Also, curvature is simply more likely

cuz it's a design compromise that is

prolly uniform in all samples, where

decentering is a manufacturing flaw

that would vary quite a bit.

 

I doubt Sony would repair any optical

failings that show up only with very

close inspection. If they are in a good

mood they might replace it, which will

most likely solve nothing, but is much

faster and cheaper than collimating, a

trick they prolly are not even equipt

to perform.

 

The general rule with optical flaws is

that you buy 3 lenses and then return

2 after testing. The warrantee does not

guarantee that no one gets the 'runt of

the litter'. If they can all hunt, then the

runt is as saleable as the champion.

 

You can pay for pick of the litter but

you can't get your pick "repaired".

 

`

[dllu]

I did the famous church tower test. There is definitely some decentering: wide open, the top left corner is significantly worse than the other three, and moreover, it is darker too for some reason.

 

Comparison of corners:

 

 

(All shot at f/1.8, 1/8000s exposure, ISO 200, manual focus, manual white balance, on a tripod)

 

 

 

I guess I will send it in for warranty.

[reeltime]

In picture 1 I can clearly see that the ranger was in motion, just look at the ghosting in the from rim of his hat.

 

In #2 I am astonished at the depth of field if that was really shot at 2.8...  I shot this lens for over a year and typically would have to go to f8 for that much depth of field!  Again a useless shot for what your looking for. 

 

#3 is useless again even at f7.1, you are about 50+ feet closer to the left edge of the image than the right edge!!!  Also I can see a very slight amount of motion blur in the overall image so I am guessing it was handheld and you did not say what the shutter speed was, not that that makes a difference considering the overall motion blur...

 

The tower shots also look like there is a significant amount of motion blur, since it looks uniform from tower to tower I will assume either you camera moved slightly or that you forgot to turn OFF Steadyshot when using a tripod which will cause blur because it is trying to correct something that doesn't need correcting, this is true with any stabilizing system...

 

Looks to me like you have a perfect copy of the FE 55 and just need to hone your skills a bit more

[dllu]

The tower shots were at 1/8000 s on a tripod. There is no possibility for blur. The Sony a7R does not have "Steadyshot" or any sort of image stabilization.

 

As anyone who has studied optics knows, the depth of field increases when shooting objects far away. That is why #2 has a deep depth of field. You could shoot wide open the stars and find them all perfectly in focus even though some are light years closer than others.

 

The shutter speed in all of the attached photos are clearly evident in the EXIF data. There is no need for me to mention it separately, but you will find that most of them are 1/400s or faster and I certainly don't suffer from Parkinson's disease or anything like that.

 

I seem to have far more success getting consistently sharp shots with the Voigtlander Nokton 50mm f/1.5.

 

I can't really consistently reproduce the aberrations in the FE 55mm though. It may well be that certain aspects of my skill is lacking or there is something loose in the lens mount or the lens that causes it to work correctly only some of the time. There is definitely something wonky going on with the asymmetric vignetting though.

 

Anyway, I'll go and hone my skills more and report back in the distant future. Thanks for the suggestions!

[Alliumnsk]

Asymmetric vignetting might as well be due to

1.shutter (1/8000 + EFCS => don't expect it to work perfectly)

2.sensor (microlens failing to cope with extreme angles)

[Austerror]

So everyone seems to think its not a problem.

 

Sell it on ebay and buy another or different lens.  Problem solved.

[Guest all8]

 

 

I did the famous church tower test. There is definitely some decentering: wide open, the top left corner is significantly worse than the other three, and moreover, it is darker too for some reason.

 

At the bottom of this page is the following text:

 

Diese Stärke an Dezentrierung wird bei Canon noch als normale Fertigungstolleranz angesehen.

 

which translates to the de-centering shown here is considered normal by Canon. And I think your lens is performing better.

 

 

I would suggest trying against that tall office block in the mid ground, and using a moderate shutter speed, say 1/1000. But the lens looks fine to me, but buy another one and do a comparison, sell or return the one with less performance.

[EDBR]

My 55mm left edge same problem, any news ?