What is crop factor and how do I use it?

Crop factor is the ratio between a full frame sensor diagonal and your sensor diagonal. Multiply your focal length by it to get the full frame focal length that would give the same field of view. A 35mm lens on a 1.5x APS-C sensor frames like a 52mm lens on full frame, so the crop makes lenses appear longer.

Does crop factor change depth of field?

Not directly, but the framing change does. If you match the field of view between formats by using a shorter lens on the smaller sensor, and shoot from the same distance at the same f-number, the smaller sensor gives more depth of field. The usual shorthand is that depth of field is deeper on smaller formats at equivalent framing.

What is the crop factor for Super 35?

Roughly 1.4 to 1.5 relative to full frame, depending on the exact sensor dimensions, because Super 35 is not one fixed size. Many cinema cameras sit around 1.5x. Micro four thirds is 2.0x, Canon APS-C is about 1.6x, and most other APS-C sensors are about 1.5x. Full frame is 1.0x by definition.

Do I lose light with a crop sensor?

No. An f/2.8 lens transmits the same amount of light per unit area regardless of sensor size, so exposure is unchanged. What changes is total light gathered across the whole sensor, which is why a full frame sensor generally has better noise performance at the same ISO. Exposure settings do not need adjusting for crop factor.

How does open gate recording change the crop?

Open gate uses the full sensor area rather than a 16:9 slice, so the effective crop factor drops and the lens covers a wider field. It also demands a lens that covers the full sensor circle. Open gate is mainly used to give reframing headroom in post and to shoot anamorphic without wasting sensor.

Which focal lengths should a cine prime set cover?

On Super 35 a classic set is 24, 35, 55 and often 16 and 75mm, which maps to roughly 36, 52, 82, 24 and 112mm full frame equivalent. That covers a wide establishing frame, a natural two-shot, a comfortable single and a flattering close-up, which is why those focal lengths recur across manufacturers.

Crop Factor and Field of View Calculator

Short answer

Multiply focal length by the crop factor to get the full frame equivalent: a 35mm lens on a 1.5x APS-C sensor frames like a 52.5mm lens on full frame. Micro four thirds is 2.0x, Canon APS-C about 1.6x, most other APS-C 1.5x, and Super 35 roughly 1.4 to 1.5x.

Crop factor is the arithmetic that decides which lens you actually need, and it is the reason a prime set that works on full frame feels wrong on Super 35. For a Super 35 cine build the Sirui Night Walker S35 T1.2 Cine Set (24, 35, 55mm) at around $749 covers the standard focal lengths for that format, and the calculator below shows what each of them frames like.

Calculator

Runs in your browser

Pick your sensor format and a focal length. The readout gives the full frame equivalent, the field of view in degrees, and the lens you would need on another format to match the framing.

Your sensor format

Focal length in mm

Compare against

Subject distance in metres

Full frame equivalent

0 mm

crop factor

Horizontal field of view

0 deg

vertical

Frame width at distance

0 m

height

To match this framing on the comparison format

The formulas

Equivalence. Full frame equivalent focal length equals your focal length multiplied by your crop factor. A 24mm on micro four thirds is a 48mm equivalent.

Field of view. Horizontal field of view in degrees equals 2 x arctan(sensor width / (2 x focal length)). Full frame is 36mm wide, so a 50mm lens gives about 39.6 degrees horizontally.

Frame width. At a given distance, the visible width equals 2 x distance x tan(fov / 2). This is the number that actually matters when you are deciding whether a two-shot fits in a small room.

Crop factors you need to know

Format	Approximate size	Crop factor	A 35mm lens frames like
Full frame	36 x 24 mm	1.0x	35 mm
Super 35	about 24.9 x 14 mm	about 1.5x	52 mm
APS-C, most brands	23.5 x 15.6 mm	1.5x	52 mm
Canon APS-C	22.3 x 14.9 mm	1.6x	56 mm
Micro four thirds	17.3 x 13 mm	2.0x	70 mm
1 inch type	13.2 x 8.8 mm	about 2.7x	95 mm

Super 35 is the one that causes confusion, because it is a film heritage term rather than a fixed dimension. Different cinema cameras label slightly different sensor areas as Super 35, so the crop factor lands between roughly 1.4 and 1.6. Check your camera's stated sensor dimensions if the difference matters for a specific shot.

Why this matters when buying lenses

What each of these frames like

The same lens covers different ground on different bodies, and coverage matters as much as focal length: an APS-C designed lens vignettes badly on full frame.

Starter zoom $549.95

Sigma

Sigma 18-50mm f/2.8 DC DN

A constant f/2.8 APS-C zoom small enough that a gimbal barely notices it, which is why it ends up on so many solo rigs.

Aperture: f/2.8 constant
Coverage: APS-C

Crop sensor only.

Check price

Fast zoom $514.99

Sigma

Sigma 18-35mm f/1.8 Art

The f/1.8 zoom that made Super 35 filmmaking cheap, and it still holds up on a Blackmagic body with a speed booster or an EF mount.

Aperture: f/1.8 constant
Coverage: APS-C

Heavy, and it needs lens support on rods.

Check price

Expert zoom $2,448

Sony

Sony FE 24-70mm f/2.8 GM II

The lightest of the fast full-frame standard zooms, with minimal focus breathing for a stills-designed lens, which matters more on video than sharpness charts do.

Aperture: f/2.8 constant
Coverage: Full frame

The one lens answer for a solo full-frame rig.

Check price

The Sigma 18-50mm f/2.8 DC DN at 18 to 50mm on an APS-C body frames like 27 to 75mm on full frame, which is a genuinely useful documentary range. The Sony FE 24-70mm f/2.8 GM II covers 24 to 70mm on full frame natively, and if mounted on a crop body would frame like 36 to 105mm, losing the wide end entirely.

That is the practical trap: a lens designed for full frame works on a crop body but loses its wide angle, while a lens designed for APS-C on a full frame body either vignettes or forces the camera into a crop mode. Check coverage before focal length. The lens mount and adapter guide covers what adapts to what.

Common framing distances

Some useful reference points at a 3 metre subject distance, on a full frame sensor:

Focal length, full frame	Horizontal FOV	Frame width at 3 m	Typical use
16 mm	96.7 deg	6.75 m	Wide establishing, tight interiors
24 mm	73.7 deg	4.50 m	Room wides, walking shots
35 mm	54.4 deg	3.09 m	Natural two-shot, the documentary default
50 mm	39.6 deg	2.16 m	Single, mid shot
85 mm	23.9 deg	1.27 m	Close-up, flattering compression
135 mm	15.2 deg	0.80 m	Tight close-up, isolated background

Focal length changes more than framing

A longer lens from further away compresses apparent distance between subject and background, and a wider lens from closer exaggerates it. That is a perspective effect of camera distance rather than of the lens itself, but since focal length dictates how far back you stand for a given frame, the two are inseparable in practice.

Practically: to make a background feel close and looming, use a long lens and stand back. To make a room feel large and a subject embedded in it, use a wide lens and get close. Changing sensor format changes which lens does that job, which is the entire reason this calculator exists.

Open gate and anamorphic, briefly

Open gate uses the full sensor height rather than cropping to 16:9, which lowers the effective crop factor and gives reframing headroom in post. It requires a lens that covers the whole sensor area and produces larger files. Anamorphic lenses squeeze a wider field onto the sensor and are desqueezed in post, so a 2x anamorphic on a 50mm lens covers horizontally like a 25mm while keeping the vertical framing of a 50mm.

Next, from here

Depth of field calculator
How much focus margin each focal length gives.
Sensor size reference chart
Dimensions and crop factors in one table.
Best cine lenses
Matched sets for Super 35 and full frame.
Best video lenses
Autofocus zooms and focus breathing.
Lens mounts and adapters
Coverage, flange distance and what adapts.
Hyperfocal distance
Where to focus for maximum depth.

Common questions

What is crop factor and how do I use it?: Crop factor is the ratio between a full frame sensor diagonal and your sensor diagonal. Multiply your focal length by it to get the full frame focal length that would give the same field of view. A 35mm lens on a 1.5x APS-C sensor frames like a 52mm lens on full frame, so the crop makes lenses appear longer.
Does crop factor change depth of field?: Not directly, but the framing change does. If you match the field of view between formats by using a shorter lens on the smaller sensor, and shoot from the same distance at the same f-number, the smaller sensor gives more depth of field. The usual shorthand is that depth of field is deeper on smaller formats at equivalent framing.
What is the crop factor for Super 35?: Roughly 1.4 to 1.5 relative to full frame, depending on the exact sensor dimensions, because Super 35 is not one fixed size. Many cinema cameras sit around 1.5x. Micro four thirds is 2.0x, Canon APS-C is about 1.6x, and most other APS-C sensors are about 1.5x. Full frame is 1.0x by definition.
Do I lose light with a crop sensor?: No. An f/2.8 lens transmits the same amount of light per unit area regardless of sensor size, so exposure is unchanged. What changes is total light gathered across the whole sensor, which is why a full frame sensor generally has better noise performance at the same ISO. Exposure settings do not need adjusting for crop factor.
How does open gate recording change the crop?: Open gate uses the full sensor area rather than a 16:9 slice, so the effective crop factor drops and the lens covers a wider field. It also demands a lens that covers the full sensor circle. Open gate is mainly used to give reframing headroom in post and to shoot anamorphic without wasting sensor.
Which focal lengths should a cine prime set cover?: On Super 35 a classic set is 24, 35, 55 and often 16 and 75mm, which maps to roughly 36, 52, 82, 24 and 112mm full frame equivalent. That covers a wide establishing frame, a natural two-shot, a comfortable single and a flattering close-up, which is why those focal lengths recur across manufacturers.

Totalling your own rig weight against your gimbal payload? The Camera Rig Build Planner is the paid version of these pages: 8 printable worksheets you fill in with your own numbers, plus the full PDF, $29.