I have just bought a Canon r5. O have 3 sigma lenses. 18-25, 70-200 and the 150-600. The larger lenses work fine but when I attach the 18-35mm lens the aspect ratio goes to 1.6x and it is impossible to change it back. I'm thinking this is because with the standard ef to rf adapter and the wide angle of the lens it wouldn't work if not at 1.6. But I have so far not come across anything on this issue. Any help would be great. Thanks
Was your previous Canon camera fitted with an APS-C sensor, and were the lenses suited to that camera instead of a full frame camera, if you can understand me. No doubt other members can explain it better than me Roy
The Sigma 18-35 is an aps-c lens. That is what cameras this lens was designed for. So when you attach it to your camera, it will then default to 1.6x ratio which is aps-c equivalent. So this is to be expected. A nice lens by the way. Gary
I bought my R5 a few weeks ago and have had issues with two of the three lenses so far. The EF-S 17-55m (used with the EF-S to R adapter) was restricted to only part of its range by being an APS-C lens (which I didn't know at the time) and none of the blurb/manuals I have read so far made any mention of the loss of functionality thus caused. Now, my RF 24-240mm lens shows the lens barrel when set to its widest setting! Canon haven't responded with an answer yet, but if they can't make their dedicated RF lens work at full frame and wide angle on an R camera, I have no faith in any of their other offerings and will have to return the entire camera kit. I can't keep buying lenses only to find they aren't working properly. Fingers crossed, but I can't see how what seems to be a physical problem with the lens design can be addressed.
Since this seems to be widely reported for that lens, it seems that they thought that using a profile to correct the vignetting was the best solution, personally I think they would have been better off with a 50-240 or something like that since trying to force a lens to go that long and that wide was going to push the limits of design. I would urge you to remember you have invested a few grand in a camera, then bought a sub $1000 non-pro / consumer grade lens that is trying to do everything in a single package. It will have limitations, and theses days they can correct a lot with post processing.
Thanks. It may be a relatively cheap lens but it is designed specifically to work with the R series cameras. If they couldn't get it to work fully over the range they should not have produced it. My Sony RX10mk4 has a superb 24-600mm zoom lens (not full frame obviously) and the Canon is only trying to cover around half that range. I really don't expect to have use software to correct a 'simple' 24mm photo. As ever, I appreciate the response.
