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Old 21-06-2021, 02:34 PM
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gregbradley
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Suggestions on repairing a Sigma Art 35 1.4 FEmount?

I have had 2 Sigma Art 35mm F1.4 lenses. The first one was a Canon mount and it did not respond well to being mounted on my Sony A7riii camera with the adapter.

Later I got another version but this one with the Sony FE mount.
It worked fine for a while. Then suddenly with no obvious reason the aperture does not adjust and its stuck at F16 or something.

Any suggestions?

Greg.
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Old 21-06-2021, 04:17 PM
JA
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Originally Posted by gregbradley View Post
I have had 2 Sigma Art 35mm F1.4 lenses. The first one was a Canon mount and it did not respond well to being mounted on my Sony A7riii camera with the adapter.

Later I got another version but this one with the Sony FE mount.
It worked fine for a while. Then suddenly with no obvious reason the aperture does not adjust and its stuck at F16 or something.

Any suggestions?

Greg.
Sorry to hear of your problems Greg, especially given the image capabilities of the 35. Other than to recommend you enlist the services of someone like The Camera Clinic to investigate all I can do is try to piece things together somehow by way of detective work, so....

To summarise (for my benefit): you have had 2 different Sigma35mm Art lenses fail when mounted to a Sony A7Riii, either directly or via an adapter. To try and help piece together what may be going on can I ask:
1. Was it the same Sony A7Riii used with both lenses?
2. Did you try testing either of these lenses on another Canon or Sony body after noticing the failure on the Sony A7Riii? Do you still have both lenses?
3. Was the adapter you used one which communicates info to and from the lens to the camera body or was it a mechanical "dumb" adapter?
4. Was the adapter you used the Intelligent adapter developed by Sony/Canon - I don't recall which, but I think it was Sony.

BEFORE DOING EITHER OF THE FOLLOWING TESTS (5 & 6) CAREFULLY INSPECT THE CAMERA ELECTRICAL CONTACTS FOR ANY DAMAGE / DEBRISor POSSIBLE WAY THEY COULD DAMAGE THE LENS CONTACTS and/or have the Camera Body tested by a Sony service agent.
5. Are you able to test the Sony A7Riii with a Sony Manufactured lens?
6. Are you able to test the Sony A7Riii with another Sigma Manufactured lens?
Maybe with some of the above we can work out what's going on. Maybe dirty or defective lens contacts/wiring on the Sony A7Riii could be the cause if that's the common factor. Who knows some more tests /detecting may help prove things out. Also camera firmware?

Best
JA

Last edited by JA; 22-06-2021 at 08:38 AM. Reason: typo
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Old 22-06-2021, 10:24 AM
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Greg,

Another thing I should have asked, when the lens was stuck with the aperture closed to f/16, was it consistently stuck there or did it come and go, mounting/dismounting the lens? Maybe the aperture blades are stuck- that can happen.

Best
JA
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Old 23-06-2021, 10:49 PM
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Greg,

Another thing I should have asked, when the lens was stuck with the aperture closed to f/16, was it consistently stuck there or did it come and go, mounting/dismounting the lens? Maybe the aperture blades are stuck- that can happen.

Best
JA
Yes they remain stuck no matter the state of on or off, or on camera or off camera.

Greg.
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