So I finally got my R7 and now Im stuck on the glass. I was looking at those RF 600mm and 800mm f/11 primes because the price is honestly great for my $1200 budget but then I read a bunch of reviews saying the small aperture is a nightmare for morning shots. I'm heading to Yellowstone in three weeks so I need to decide fast.
My logic was that the crop factor gives me crazy reach anyway but then people keep mentioning the old EF 400mm f/5.6 with an adapter. It’s older tech though so I’m worried it wont keep up with the R7 autofocus system. Should I stick with the modern RF primes or go the adapted route for more light? I really just want something sharp for bison and bears...
In my experience, f/11 is a total nightmare for Yellowstone dawn. Ive tried many setups over the years and honestly, the Canon EF 400mm f/5.6L USM is still a beast. The AF is surprisingly snappy on the R7 with the Canon Mount Adapter EF-EOS R. Its way sharper than those budget RF primes and that extra light is a lifesaver for bears... go the adapted route.
To add to the point above: I have been very satisfied with the Canon EF 300mm f/4L IS USM for wildlife. It works well on the R7 because that f/4 aperture is so much more versatile than the f/11 options when you are shooting in the early morning light at Yellowstone. I have had no complaints about the AF tracking speed when using the adapter; it is snappy enough for moving animals and the sharpness is quite impressive for older glass. One quick tip for the R7: keep an eye on your ISO. Even though f/4 is better than f/11, that sensor has very small pixels and noise can creep in fast. I usually find that sticking to a slightly shorter prime like the 300mm and cropping in post works better than using a darker 800mm that forces your ISO too high. It is a very practical way to maintain image quality while staying within your budget.
