How we check

Where the facts come from

Camera specifications come from each maker's specification page (Canon Europe, Sony's support pages, Fujifilm and Nikon). Lens specifications come from the makers' pages and the lens tables on Wikipedia, spot-checked against the makers. These are stable specifications: they do not change once a model exists, so each carries its source and no date or expiry; if a maker corrects a figure, we correct it. Where a maker publishes no figure, the field is left empty and the page says so; nothing becomes zero.

The whole catalogue is downloadable: every lens on every camera as CSV and the catalogue as JSON, under CC BY 4.0.

What “fits” means

A lens fits a camera when it is made for the camera's mount: Canon RF, Sony E, Nikon Z or Fujifilm X. On its own mount a lens fits and works, with autofocus, aperture control and the camera's lens corrections, unless its maker publishes a condition for the pair. Sony publishes a page for every camera and lens pair; we read all 576 Sony pairs in the catalogue and quote Sony's words beside each. Canon, Nikon and Fujifilm publish exceptions, which we quote where they exist. A lens on another mount does not fit; the makers' own adapters for their DSLR lenses have their own pages.

Why a lens is picked first

Each camera page picks one lens per job by a rule stated beside it, from the numbers: everyday and travel, a zoom from about 28 mm to at least 70 mm equivalent, lightest first; people and portraits, the brightest prime framing like 70–135 mm that weighs under 300 g; wide scenes and rooms, the widest zoom under 600 g, lightest on a tie; distant subjects, reach of at least 300 mm equivalent under 1.5 kg, longest reach per gram; close-up and macro, life-size (1x) or more, lightest first; otherwise the highest magnification; low light, f/1.4 or brighter framing like 35–60 mm, lightest first. No pick is paid for, and a commission cannot change a rule.

Equivalent focal length

Equivalent focal length compares the view with a full-frame camera: the lens's focal length times the crop factor, rounded to the millimetre. We use each maker's own factor: 1.6 for Canon's APS-C cameras and 1.5 for Sony, Nikon and Fujifilm. It changes the framing, not the lens. The framing drawings size each frame in inverse proportion to the equivalent focal length, so a 24 mm-equivalent frame is twice as wide as a 48 mm one. Camera and lens drawings use the makers' published sizes at one scale; their inner details are simplified.

Filter threads and step-up rings

A filter of the lens's thread size screws on directly. A larger filter fits through a step-up ring; a smaller one would darken the corners, so we never suggest a step-down. The kit's filter size is its largest thread, with a ring for each smaller one. A ring usually stops the lens hood fitting.

What a weight includes

A camera's weight is its maker's figure with battery and memory card. A lens's weight is its maker's figure, without caps or hood. “With the camera” adds the two. The kit builder adds the accessories you enter; an item without a weight is counted separately, never as zero. Ounces convert at 28.349523125 grams each.

Depth of field, field of view and crop factor

The depth-of-field calculator uses the thin-lens model. With focal length f, f-number N, circle of confusion c and focus distance s, in millimetres: K = f² / (N × c); hyperfocal distance H = K + f; near limit = K × s / (K + s − f); far limit = K × s / (K − s + f), infinite when s ≥ H. The default circle of confusion is the sensor diagonal divided by 1500; diagonal / 1000 and your own value are offered. It leaves out focus breathing, distortion and close-up magnification.

The field-of-view calculator uses angle = 2 × atan(sensor dimension / (2 × focal length)); the frame at a distance is distance × sensor dimension / focal length; the distance to fit a subject is subject height × focal length / sensor height (sensor width with the camera upright).

The crop-factor calculator uses the makers' factors for named cameras and the diagonal ratio (43.27 mm divided by the sensor diagonal) for a sensor you enter. Equivalent aperture multiplies the f-number by the factor for depth of field at the same framing; exposure still uses the actual f-number. A zoom's widest aperture between its ends is not published, so it is not checked there.

Drawings

Every drawing on this site is drawn from these numbers in code: no photograph is altered and no drawing is decoration. Product photographs appear only where Amazon supplies them through its approved image service, or where a photographer's licence allows, with credit.

Facts from the makers' specification pages. How we check