Issue with Samyang AF 35mm F1.4 FE on Sony a7R During Long E

[enapp]

Hello everyone,

I am experiencing an issue with my new Samyang AF 35mm F1.4 FE lens on my Sony a7R camera, and I am hoping someone here might have encountered something similar or could offer some advice.

Whenever I take long exposure photos with this lens, I notice dark shadows and shapes appearing in the images. This happens even when I am not using the lens hood. The issue is not present or noticeable during shorter exposure shots, but it becomes quite apparent with longer exposures.

Here are the steps I have taken to troubleshoot the problem:

• I have tried shooting with and without the lens hood, but the issue persists.
• I have ensured that the lens is securely attached to the camera.
• I have checked the camera sensor for dust or damage, and everything appears to be fine.
• The problem only seems to occur during long exposure shots.

Since the lens is brand new and this is the first time I have used it, I am concerned that there might be a defect. Has anyone else experienced this issue with this lens or any other lens? Any insights or suggestions would be greatly appreciated.

Thank you for your help!

Best regards,

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[Cameratose]

You don't provide any information about the camera settings. Is this indoors? Outdoors? Either one? Is it under fluorescent lighting? LED lighting? Any lighting? Have you tried the anti-flicker setting?  

I've shot the Samyang 35/1.4 on an A7R III, A7 IV, and A1, and haven't seen this. My longest exposure so far was probably about 1/4 second, not sure what you're referring to as long exposure though.

What you're seeing is not related to the hood or vignetting. If it's not showing up using normal exposure settings, it is unlikely to be a lens issue. Do you know anyone with a Sony you can run tests with? What about other lenses at the same exposure settings? 

The best way to determine what's happening is through the process of elimination, but always try only one change at a time. If you change more than one and you fix it, you won't know which one did the trick.

[enapp]

18 hours ago, Cameratose said:

You don't provide any information about the camera settings. Is this indoors? Outdoors? Either one? Is it under fluorescent lighting? LED lighting? Any lighting? Have you tried the anti-flicker setting?  

I've shot the Samyang 35/1.4 on an A7R III, A7 IV, and A1, and haven't seen this. My longest exposure so far was probably about 1/4 second, not sure what you're referring to as long exposure though.

What you're seeing is not related to the hood or vignetting. If it's not showing up using normal exposure settings, it is unlikely to be a lens issue. Do you know anyone with a Sony you can run tests with? What about other lenses at the same exposure settings? 

The best way to determine what's happening is through the process of elimination, but always try only one change at a time. If you change more than one and you fix it, you won't know which one did the trick.

Thank you for your quick response and detailed questions.

To provide more context:

• The issue occurs both indoors and outdoors, under various lighting conditions including natural light, fluorescent light, infrared light, and even in darkness.
• I have not tried the anti-flicker setting yet, but I will give that a try to see if it helps with the issue.
• When I refer to long exposure, I mean exposures longer than 1 second. The specific shots where I noticed this issue had an exposure time of 3 seconds in darkness.
• Unfortunately, I do not have access to another Sony camera, and this is the only lens I have for this mount. Both the camera and the lens are brand new.
• Additionally, I have noticed that when I change the focus, whether manually or automatically, the "shadow" or "glare" also changes. This seems to be tied to the focus adjustments.

I appreciate your suggestion on the process of elimination and will take that approach to see if I can isolate the cause. I will start by testing the anti-flicker setting.

Thank you again for your help. I will update you with any findings after these tests.

[Cameratose]

This sounds a lot like the lens. The anti-flicker is a long shot anyway, and after hearing your explanation probably won't help. I would get ahold of the seller and start a return process. 

[enapp]

29 minutes ago, Cameratose said:

This sounds a lot like the lens. The anti-flicker is a long shot anyway, and after hearing your explanation probably won't help. I would get ahold of the seller and start a return process. 

Thank you very much for your advice. I wasn't sure if this was a common issue or a configuration problem, especially since this is my first Sony and Full Frame camera. I appreciate your input, and I will go ahead and contact the seller to start the return process.

Thanks again for your help!