D-Noc wrote in post #19417723
You will most likely be disappointed. I know I was. I bought the Sigma 50mm f/1.4 EX DG HSM (the Non-Art) way back, and used it on my 6D. But getting focus right required a lot of MFA and still it never got really good. Even after MFA the focus would be off depending on the distance to the subject, so it got a lot of shelf-time.
The I bought the R, and thought more or less exactly as you in the quote. And at first it really did seem like the lens could finally live up to its potential.
..but then I noticed that all the images were ~1-1.5 stops underexposed. I tried adjusting all kinds of camera settings, but only overexposing what I saw in the EVF would solve it and obviously this ended up being even more annoying than the somewhat schizophrenic focusing it had on my 6D. I googled it, and apparently it is an issue caused by the reverse engineering Sigma has done to get the lens talking with the camera. Apparently it disguises itself a another lens, and that throws off the metering in the camera.
When I got my R6, I hoped it would be better, but unfortunately the issue persisted, so I ended up selling the Sigma.
Interesting. I have a pre-Art one, too, but I don't think I've tried it with the R-series cameras I have. It's too bad that the cameras don't have the ability to recognize a lens and apply a user bias to settings like EC, or lens corrections, or focal lengths, but if most of the issues are with non-OEM lenses, that removes the incentive for Canon to implement it. If the focal length is wrong, the pitch/yaw correction in the IBIS will be wrong, too. If the reported FL is too short, it will just under-correct and correct somewhat, but if it is too long, the motion will be over-compensated and reproduced in the opposite direction. If you use a contact-less adapter like the Hoage (less yucky than tape, IMO!), you can dial in the focal length yourself, but then you have no camera control of aperture or AF.