[Klaus]

---> attachment

Yes, it is, of course, the usual highlight test but what about the shape?

* I removed the square-shaped hood -> it's not the hood
* the effect is similar at other smaller apertures but gone from f/2 (but this may just mask the effect) - but a frequency issue with the light seems unlikely.
* I can't spot something "square" in the lens
* the effect is also visible in other, more "normal" images

I really don't have an idea at the moment.

[Rover]

I was more intrigued by the number in the filename...

[Brightcolours]

Weirdly enough, the EXIF says SONY ILCE-6300, and Tokina atx-m 56mm f1.4 E.

If you shared which f0.95 lens you are testing, and on which camera, it would be easier to explain what we are seeing.
Somehow, it does look like the rectangular surrounding of the A6300 shades the light, but that means that the light from the lens enters at a rather very extreme angle. 7artisans 25mm f0.95?

---

Yep. I was right, I think? The 25mm f0.95 has the focal point very close to the sensor due to the short focal length, and a large aperture. The Fuji cameras do not have a similar problematic sensor surround as the Sony cameras do, and as such do not show the rectangular shading with the same lens.

[Klaus]

It's the Laowa 33mm f/0.95 APO on the A6300

No EXIF data, so it takes the lens name from the one used before.

If the light entered at such an extreme angle, there should be color tint issues in the corners? I can't spot any. The vignetting is also "normal".

[Brightcolours]

Non-focussed light (bokeh balls in the background) hits at a different angle than the focussed light. The same Sony rectangle issue can be observed with the mentioned 25mm f0.95 (https://www.youtube.com/watch?v=xtONaZwA7ug&t=168s). If you test the same lens on a Fuji (with Fuji mount of course) you will not see the shading from the rectangular sensor surround.

Test this: mount the lens on your FF A7 body. The rectangular shading will magically disappear.

[Klaus]

You are correct. :-) See the quick 'n dirty shot in the attachment.

Still a bit surprising - the rear element isn't overly curved.

[Rover]

Wow, I think it's the worst I've ever seen?

[Klaus]

The last image is on FF - but this is an APS-C format lens. It was only meant to confirm BC's theory.