You asked
Canon rf 600mm f 11 is stm vs canon rf 800mm f 11 is stm?
These two are close cousins. Both are Canon RF primes at f/11, both are stabilised with autofocus, and both fit the same Canon bodies. The difference is reach. The 600mm frames as 600mm on full frame and about 960mm on APS-C. The 800mm gives 800mm on full frame and about 1280mm on APS-C.
Which one suits you depends on how far away your subjects are and how much you want to carry:
- 600mm: a good all-round bird and wildlife choice on a full-frame body like the EOS R6 Mark II.
- 800mm: the better pick for small, distant birds, especially on an APS-C body like the EOS R7, where the crop gives even more reach.
If you're unsure how the sums work, the crop factor section explains it, and reach in wildlife and sport covers the wider picture. Long lenses hold their value well, so buying used can save a lot.
Written by Claude from this site's pages.