OP’s contemplated EF 100–400 II is on the list of lenses supporting high frame rates, and I can confirm it does on the R3. (Older copies need a firmware update, and OP should confirm the R7 can apply them to lenses before buying that combination, otherwise they would have to borrow a body that could.)
Respectfully, that’s not correct. The EF 400mm f/5.6L does not limit high frame-rate shooting on the R7, R6 series, or R3—FPS is governed by the camera body and shutter mode, not the lens. The trade-offs here are no IS and f/5.6 in low light, not burst speed.
I just tested it on my R3 with another lens that doesn’t support high frame rate, the EF 70–200mm f/4 IS from 2006. The actual behaviour is that the camera will let you select "H+" 30fps in electronic shutter, but when I fire off a burst the camera throttles it to ~15fps. I determined the achieved frame rate by inspecting the SubsecTimeOriginal EXIF field, which the camera writes to the resolution of 0.01s. Values were consistently 0.05s and 0.06s apart. The shutter speed was above 1/125s as required for 30fps; shot outside on a bright sunny day with the target a bush in shade being blown about a bit by the wind, IS off.
This is consistent with the link at Canon I posted above – which you quoted in your reply to me I quote from in this post - that also says the 4-5-6, like the lens I tested, can’t do 30fps.
Feb 02, 2026 at 02:50 AM
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