Canon Patent Turns Precapture On by Itself When You Reach for a Long Lens

Precapture is one of the best things mirrorless cameras have given action shooters, and it only helps if you remember to switch it on. Canon was granted a US patent in August 2026 for a camera that makes that call for you, based on the lens on the front and what’s in the frame.

The patent is US 12,712,981, “Image pickup apparatus that reduces loss of opportunities for photographing.” It was first filed in Japan in May 2023, filed in the US in May 2024 and granted on August 18, 2026. The inventor is Kenta Ihara.

The problem in Canon’s own words

Precapture, which Canon calls pre-continuous shooting on bodies like the EOS R5 Mark II, keeps shooting into a buffer while you hold the shutter button halfway. When you press fully, the camera saves the frames from just before as well as after. The bird left the branch before your finger moved, and you still have it.

The patent’s background section names the weak point bluntly. If the photographer meant to use precapture but forgot to enable it, a half press does nothing special and the shot is lost. Anyone who has turned precapture off to save battery or card space, then met a hawk on the walk back to the car, knows the feeling.

When the camera decides

The granted claim is specific. Precapture switches on automatically when the lens focal length is at or above a set threshold, and when the camera detects a subject in the frame. If nothing is detected, it stays off even with a long lens mounted.

The logic is easy to follow. Long focal lengths go with birds, sports and anything else that moves fast and far away. Requiring a detected subject stops the camera from filling its buffer while you’re pointing a 600mm lens at an empty sky. Canon says that check is there to keep power use down. You can still turn the function on or off yourself; the claim covers a manual switch too.

The wilder triggers in the description

The claim is narrow, but the description that comes with it goes much further. Canon describes a “photographing failure probability evaluation value,” a score for how likely the shot is to fail if the camera waits for the full press. The inputs it lists include focal length, aperture and depth of field, how big the subject is in the frame, subject speed, how much the camera is moving, shutter speed, scene brightness, blur and image stabilization data.

Then the list goes somewhere you wouldn’t expect from a camera company: biological information about the photographer, such as blood pressure, brain waves and line of sight. The idea seems to be that a racing pulse or eyes locked on a subject say “something is about to happen” as clearly as a fast-moving target does.

Other variants switch precapture on when the aperture is opened wide, since shallow depth of field makes a missed moment more likely, or when a small, fast subject such as a bird or an airplane is detected. One version also turns precapture off again if the subject slows down below the trigger speed, so the camera isn’t recording a buffer of a now-idle subject.

What it would change

Most of this is a firmware feature, which is why it matters. Bodies with precapture, from the R5 Mark II to the EOS R6 Mark III with its 20-frame buffer, already have the hardware. An “auto” option driven by focal length and subject detection would be a sensible default for wildlife lenses such as the RF 200-800mm F6.3-9 IS USM, and it costs nothing to build.

The heartbeat trigger is another matter. A camera would need a way to read your pulse, perhaps through a paired watch, and that sits firmly in the someday pile. But the core of the patent is modest and practical: stop making photographers remember a menu setting at the moment they need their hands for everything else.

For how precapture works on Canon’s top bodies today, see our Canon EOS R5 Mark II review.

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