
Common fixes
What fixes the R10's known problems — 4K that won't record, adapted lenses, focus that won't track?
4K stops — or never starts
Work the checklist in order. Format: Canon’s manual says to low level format the card before 4K recording. Card speed: 4K at 10-bit (HDR PQ) at the top rates needs a V60 card by Canon’s requirements; 8-bit 4K asks for UHS Speed Class 3 — a slow card stops recordings or fails them outright. Heat closes the list: a hot camera offers less recording time.
It won’t fire — and it won’t steady
A manual or adapted lens with no electronic contacts leaves the shutter dead until Release shutter w/o lens is set to ON (Custom Functions tab). The stabilization half is honest: this body has no in-body stabilizer and no [Focal length] entry, so silent glass shoots unstabilized for stills. For movies, Movie Digital IS can stabilize even a non-IS lens.
No tracking frame, ever
Subject to detect is set, Servo is on, and no tracking frame appears: the cause is Subject tracking itself. Set it to On. The manual states it twice — with Subject tracking off, no tracking frame is displayed regardless of the Subject to detect setting, and eyes are not detected either.
The honest answer: it isn’t here
Focus breathing — the frame pulsing at the edges as focus racks — is corrected on bigger Canons by a Focus breathing correction item. This body does not have it: Lens aberration correction here lists Peripheral Illumination, Distortion, Digital Lens Optimizer, Chromatic Aberration and Diffraction only. Manage breathing with lens choice, shorter focus throws, and cuts.
Rehearse the fixes now: low level format the card you shoot 4K on, confirm Subject tracking is On, and find Release shutter w/o lens before an adapted lens surprises you in the field.