I picked up an R50 to test out the canon waters. I really like the overall system and especially the output and can see moving in the direction of an R6II at some point. For now, though, I need to build my lenses.
Canon was at my local camera store last month and I got to try out the 28-70mm 2.8. Surprisingly, I found it fairly quick and silent unlike the 35mm 1.8 I have.
Question I have is if anyone has tried this lens for faster action. I like to get my dog running around and other modestly fasted paced events with people. I'm wondering if this is good enough or perhaps, I need to look at something with a USM motor.
Unlike the earlier STM primes which have front-focusing designs, the Canon f/2.8 STM zooms use internal focusing. They also use a newer generation of STM motors, so focusing is quick.
Canon has even promoted these lenses for action photography. See here for the very similar RF 16-28mm f/2.8 STM:
Caveat: I have no experience with the R50, but the lens works well with the R6 II and R8.
