What the standard defines
A size, referenced to film. A full-frame sensor covers approximately the 36 × 24 mm area that a frame of 35 mm film exposed. No standards organisation publishes the term; each maker prints it, and each publishes the dimensions of its own sensors.
Because the reference is a film frame rather than a document, the term is stable in a way the dimensions are not: makers agree on what it points at, and differ in the last fraction of a millimetre.
What it does not promise
No grade. The format is a dimension. Ranking two cameras by format alone discards every figure that differs between them.
No lens coverage. A lens mounts, or it does not, according to its mount; whether it covers the whole frame is a separate published property. A lens cut for the smaller format mounted on one of these bodies illuminates part of the frame, and bodies that address this do so with a crop mode, described in their own sheets.
No low-light claim. Sensor area affects how much light lands, all else equal, but all else is never equal between two cameras. Noise figures, where published at all, are published per body.
No depth-of-field figure. Depth of field follows from focal length, aperture, distance and the size of the frame. The format contributes one term to that arithmetic and settles none of it on its own.
What it works with
Bodies that print the term, and lenses whose published image circle covers the frame. The smaller APS-C format, printed in twelve of this catalogue’s titles against seven for this one, shares most mounts with it — which is why the figure worth reading on a lens listing is the image circle rather than the mount alone.
What people ask before they commit
Is full-frame better than APS-C?
The format is a dimension, and a dimension is not a grade. A larger sensor changes framing for a given focal length and depth of field for a given f-number and subject distance, both by geometry. Everything else a buyer cares about — autofocus, stabilisation, noise, the lenses available and what they weigh — is published separately, and this site compares those figures rather than ranking a format.
Why is it called full-frame if there are larger sensors?
Because the reference is 35 mm film rather than the largest sensor made. Formats larger than 36 × 24 mm exist and are described by their own names. The word full points at a film frame, not at a maximum.
Last reviewed 12 September 2026