SIGMA releases new firmware for the 500mm f/4 DG HSM OS, improves performance with R5 and R6 | Canon Rumors
Bryan Carnathan once reviewed it with a 1D-X attached and discovered a focus shift issue. If Sigma could tackle this, too, for Canon’s latest (last) DSLRs, it’ll be a great alternative for Canon wildlife/sports shooters. For the R5/6 it has to focus decently speedy, otherwise it would be no serious option for e.g. birding.
