An odd A700 problem (?)

[Dhalgren]

Hi. This is my first-time post (and I subscribe to the newsletter). While I did search the forum to see if any other A700 user experienced this problem, I was unable to find an exact match so here goes.

A recent problem seems to have emerged in my A700. In all of my lenses (SIgma 18-50 2.8, Sony G 70-300 SSM, Sony 11-18, etc.) there is a recent vignetting / distortion problem. What used to be dead-center in my frame (the center focus spot), now appears slightly above the center spot in my image. At the same time, this problem is accompanied by slight vignetting at the lower corners.

Considering that this is suddenly happening to all of my lenses, at every setting and focal length I can think of, am I correct to assume that this is a mirror issue? Has anyone else experienced something like this?

This problem emerged after a day when I went to a sporting event, and swapped lenses 4 or 5 times. Nothing was dropped, and it was all done with care. But I do wonder if something became loose.

[redsim74]

Welcome to the forum, Dhalgren.

I'm thinking sensor misalignment or SSS failure but no doubt greater minds than mine will be along shortly with their opinions!

Best of luck,


Sim

[harvey]

Do you see a normal image through the viewfinder?

I was going to suggest that if you have an extra camera you post images looking into the camera with no lens attached. One with the normal mirror position and one with the mirror locked up? But maybe any sensor offset would be too hard to spot so I will leave it for others to suggest if this would help or not.

Harvey

[Dhalgren]

Very good points, thanks! My view through the finder is normal. Unfortunately, I don't have another SLR body to test.

[WaltKnapp]

If the viewfinder view did not change but the photos are out of alignment that's a sensor misalignment. One of my a700s did this, though much more offset than you describe. It was something broken in the SSS, the sensor is mounted on the SSS. SSS involves a suspension with some pretty tiny supports to make it very flexable. Occasionally those break. The SSS comes from parts as a fully assembled unit so everything gets replaced. Since alignment is then involved I'd doubt doing it DIY, send it in. Mine came back in two weeks and has worked perfectly ever since.

Walt

[Dhalgren]

Many thanks, Walt. Seems you have correctly diagnosed this problem before.

http://forums.dpreview.com/forums/read. ... e=34721332

[KevinBarrett]

Walt's answer seems spot on. That's more vignetting than I think anyone would see even with SSS turned on and compensating at its maximum, and it isn't in a regular circular pattern. The sensor would seem to be experiencing mechanical vignetting rather than simple light fall off. Look for it to be sitting far too high behind its shutter.


Welcome Walt and Dhalgren!

[Dr. Harout]

Definitely sensor/SSS misalignment or whatever it is called.
I wonder if DSLRs with no SSS/AS/SR may ever have this problem. I think not, and it might be the sole argument against in body stabilization.
And welcome Walt and Dhalgren.

[jbtaylor]

Welcome to Dhalgren and Walt.
Walt, been reading your posts on DPReview for quite some time. I think you will find things more agreeable over here. Looking forward to reading you opinions and seeing some of your work.

[WaltKnapp]

I've been reading Photoclubalpha for some time without registering so I'd not be tempted to post. But when a thread went on and on in here discussing me, I figured I better register and "defend" myself Yes it looks much nicer in here than DPReview.

Walt

[David Kilpatrick]

Welcome aboard Walt. I have followed a lot of your commentary on dPreview. I hope you try the 30mm macro, by the way - it is much better than it should be for the price and has some interesting uses because of the way its focal length shortens as you focus closer.

I have tried a couple of times, using new internet addresses, to register again on dPreview. They seem to spot me every time!

David

[Arun Gaur]

I've been reading Photoclubalpha for some time without registering so I'd not be tempted to post. But when a thread went on and on in here discussing me, I figured I better register and "defend" myself Yes it looks much nicer in here than DPReview.

Walt

Yes a thousand times nicer.
Arun Gaur
http://tripolia-indianlandscapeimages.com

[WaltKnapp]

Welcome aboard Walt. I have followed a lot of your commentary on dPreview. I hope you try the 30mm macro, by the way - it is much better than it should be for the price and has some interesting uses because of the way its focal length shortens as you focus closer.

I have tried a couple of times, using new internet addresses, to register again on dPreview. They seem to spot me every time!

David

With all the macro I have now I find it hard to justify the 30mm. I'll probably end up with it someday anyway. I'm kind of moving into bunker mode with Sony. Just keep using a700s, the last Sony DSLR that really work well for my photography. I'm up to three a700s all with the longest extended warranty I could put on them.

I mostly hang on at dPreview as a source of info on what's new from Sony. And to keep track of the factions that seem to want to turn DSLR into anything but DSLRs for top still photography. You are probably well out of there.

Walt

[Arun Gaur]

Welcome aboard Walt. I have followed a lot of your commentary on dPreview. I hope you try the 30mm macro, by the way - it is much better than it should be for the price and has some interesting uses because of the way its focal length shortens as you focus closer.

I have tried a couple of times, using new internet addresses, to register again on dPreview. They seem to spot me every time!

David

With all the macro I have now I find it hard to justify the 30mm. I'll probably end up with it someday anyway. I'm kind of moving into bunker mode with Sony. Just keep using a700s, the last Sony DSLR that really work well for my photography. I'm up to three a700s all with the longest extended warranty I could put on them.

I mostly hang on at dPreview as a source of info on what's new from Sony. And to keep track of the factions that seem to want to turn DSLR into anything but DSLRs for top still photography. You are probably well out of there.

Walt

But Walt you always get the same typical responses to your well known line of thought. They won't change their stance. So sometimes, I wonder if it is of any use getting involved with that "faction" or even keeping track of that faction.

Arun Gaur
http://tripolia-indianlandscapeimages.com

[Greg Beetham]

Hi. This is my first-time post (and I subscribe to the newsletter). While I did search the forum to see if any other A700 user experienced this problem, I was unable to find an exact match so here goes.

A recent problem seems to have emerged in my A700. In all of my lenses (SIgma 18-50 2.8, Sony G 70-300 SSM, Sony 11-18, etc.) there is a recent vignetting / distortion problem. What used to be dead-center in my frame (the center focus spot), now appears slightly above the center spot in my image. At the same time, this problem is accompanied by slight vignetting at the lower corners.

Considering that this is suddenly happening to all of my lenses, at every setting and focal length I can think of, am I correct to assume that this is a mirror issue? Has anyone else experienced something like this?

This problem emerged after a day when I went to a sporting event, and swapped lenses 4 or 5 times. Nothing was dropped, and it was all done with care. But I do wonder if something became loose.

SSS only has movement side to side, from memory, your sensor appears too be displaced downwards, (the Pentax version has another movement incorporated as well), so something has come adrift in the SSS/sensor department, it'll have to go in for repairs I'm afraid.
Greg

ps. Have you tried turning the SSS off and on a few times, just to see if it frees up? or even tuning it off altogether and taking a few shots?