RF 400 - still and EF lens at its core
RF 600 - same as above
molson wrote:
Considering those EF lenses were so far ahead of the competition back when they were released, that's not necessarily a bad thing, especially considering the RF versions focus faster, much more accurately, and have much better image stabilization.
Let's be honest here - the skill and determination of the photographer will make significantly more difference in the final image than any minute differences in lens quality between the Canon/Nikon/Sony 400mm and 600mm primes.
Yes, how much are we splitting hairs? Maybe one could say the EF versions are RF lenses at their core?
The EF versions were released in 2018, the same year as the R system's debut. There is no way these lenses were developed in isolation from the R system. It's more likely the lenses were optimized to work with both systems and that the RF versions are tuned for the differences required for mirrorless vs. DSLRs.
So while I agree that the lack of an internal TC was a missed opportunity by Canon if indeed they rushed these lenses out, and the lack of mid-tier long primes is discouraging for bird/wildlife photographers, I'm not convinced there is an AF performance penalty afflicting the 400/2.8 and 600/4 RF versions on R cameras. It seems more like the continued parroting of something someone claimed way back when these were released (just rehoused EF lenses). Has someone shown that the RF versions of these lenses aren't up to the task? From the birding photos I've seen with the 400 on the R3 in other threads here, there doesn't seem to be a problem focusing on small birds, such as swallows, in flight. Maybe @RobAmy or @stanj could comment?
