I finally upgraded to the Canon R8 and I'm planning a trip to Yellowstone next month to shoot some wolves and bears. Budget is strictly under $1500. I looked at the RF 100-400mm because it's so light but I'm really worried f/8 at the long end is gonna be too slow for low light morning shots. Everyone keeps recommending the Sigma 150-600mm adapted, but then I read posts saying the autofocus pulses bad on mirrorless.
Should I just bite the bullet on the RF 100-400 or is there a better option I'm missing?
> Should I just bite the bullet on the RF 100-400 or is there a better option I'm missing? I bought the Canon RF 100-400mm f/5.6-8 IS USM last fall hoping the lightweight design would win me over. Unfortunately, it was not as good as expected in dawn light. I had issues with autofocus hunting on moving deer at f/8, and shooting at ISO 12800 just to keep my shutter speed at 1/500s ruined several shots with noise. Since your trip is next month, have you thought about renting? I checked Lensrentals and you can get the Canon RF 100-500mm f/4.5-7.1L IS USM for under $200 for a week. If you really want to buy, check MPB for a used Canon EF 300mm f/4L IS USM. You lose the zoom flexibility, but that f/4 aperture gives you two full stops of light over the RF at f/8, which is huge for those early morning wolves.
> You should absolutely look at a used Canon EF 100-400mm f/4.5-5.6L IS II... Building on the earlier suggestion, I went this exact route last year when I was starting out because I was super paranoid about autofocus issues with third-party lenses. I ended up getting a used Canon EF 100-400mm f/4.5-5.6L IS II USM and paired it with the standard Canon Mount Adapter EF-EOS R. Honestly, it works perfectly. No pulsing or weird lag, and it felt way safer than risking a Sigma. I managed to find a refurbished adapter on the Canon site for cheap, which saved me some extra cash. The setup is a bit heavy, but the autofocus reliability and the extra stop of light over the RF 100-400 at the long end made me feel a lot more confident. If you want to save money, check out used gear sites that offer warranties, just to be safe. Let me know if you want to know how it balances on the R8 body.
Honestly, forget the Sigma, the focus pulsing on R bodies is super annoying! I love the Canon RF 100-400mm f/5.6-8 IS USM for hiking because it is incredibly light, but f/8 is tough for early morning wolves. You should absolutely look at a used Canon EF 100-400mm f/4.5-5.6L IS II USM with the adapter. It is amazing, autofocus is flawless, and it handles low light way better!
