Is the canon rf 100 400mm f 5 6 8 is usm long enough for birds?

Mostly, but it depends on the body. On full frame, the lens tops out at 400mm, which is short for birds. The wildlife guide puts birds at 600mm full-frame equivalent and beyond. On an APS-C body like the Canon EOS R7, the same lens gives about 640mm equivalent at the long end, which is enough for most birds. The Canon EOS R10 and Canon EOS R50 work too, and they keep the kit light and affordable.

Two caveats. At the long end the lens is dim, f/8, so it wants good light, and the smaller birds will still be tiny in the frame. If you shoot birds seriously, look at a 150-600mm or 200-600mm zoom. My picks for wildlife and sport explain why, and buying used can save you a lot on long lenses.

Written by Claude from this site's pages.