Sorry - deleted those test shots already. You've seen it before, I'm sure - purple fringe CA along edges of objects near outside edges and corners of frame. No, I'm not saying it's worse than on a Canon camera. I'm sure you'd see exactly the same thing on any camera with similar resolution, although I've never used this lens on a Canon, so I can't say from personal experience. The CA (chromatic aberration) comes from the lens, not the camera, but it's more apparent with higher resolution.
Ah, the purple fringing showing more because of higher resolution sensor I can understand. But then, it's all relative, isn't it? Unless the Sigma 15mm or the Tokina 10-17mm show less chromatic aberration (doubtful, certainly on the latter), the Canon 8-15 remains the best solution for a fisheye on the A7RII. And certainly the only option if you want both a circular fisheye and full frame fisheye in one lens with the ability to zoom in a bit for wide angle macro if using a teleconverter or APS-C crop mode.
Plus, chromatic aberration is pretty easy to correct in Lightroom and should not show up any more than on the Canon bodies if images are displayed at equivalent resolutions.
So Tobbe, a few years down the line.
Do you continue with the Sigma 15mm or did you go Canon 8-15 like the majority seem to do?
Cheers
/O
An update on my experience with the Canon 8-15mm & Metabones IV on the Sony a7r2 and a7r3: After a year or more of use, it started developing an occasional issue where the camera would lose communication with the lens. This is manifested by the display showing no aperture for the lens and shutter release disabled. It can be quickly corrected by twisting the lens & adaptor off the camera body and back on -- but this requires removing the camera from the housing. And of course, it's horrible when a really good subject passes in front of you and you can't take a picture with the camera that was working fine a few minutes ago. I've tried multiple methods of cleaning the little gold contacts, but the problem re-emerges. Now I always do a few twists (also twisting the lens off the Metabones & back on) before putting the camera in the housing & it usually works okay for the duration of the dive, but not always for the whole day. With my dedicated Sony lenses, I have never had this issue. btw I have both the Sony wide-angle and the fisheye converters for the Sony 28mm lens. The results with the wide-angle converter are superb, but I am not satisfied with the fisheye converter optics, so I continue using the Canon 8-15mm with MIV, and hope it won't freeze up on me. Meanwhile waiting for a dedicated Sony fisheye which should be less bulky, as well as averting camera-lens connection problems. btw - I normally shoot on shutter priority. I doubt any other exposure mode would change the dynamic, but I haven't experimented to be certain.
Reviving this thread as I'm exploring the sigma 15mm (2.8 ex DG, canon fit) for a Sony A7RIII body & housing (nauticam).
I'm not sure what is the recommended Adapter for this? Nauticam mentions a Mark III (NEX III smart adapter from metabones) but there seems to be multiple versions of the metabones adapter.
I'm using the Metabones Mk V adapter with the Canon 8-15 on my Sony A7RIV, it is the latest version and am very happy with it:
It's cheaper than the Metabones and there shouldn't be any compatability issues between lens and adapter as they are both Sigma. I have a friend using this combination on their Sony A7RIII and they are very happy with it.
