About

Crop factor quantifies how a camera sensor's size relates to the 36 × 24 mm full-frame reference. Miscalculating it leads to wrong lens choices, unexpected framing, and depth-of-field surprises that ruin shoots. The factor CF is the ratio of the full-frame diagonal (43.27 mm) to your sensor's diagonal. A 50 mm lens on a 1.5× crop body frames like a 75 mm lens on full frame. The aperture equivalence shifts too: f/1.4 on that same body delivers depth of field comparable to f/2.1 on full frame. This tool computes crop factor, equivalent focal length, horizontal and vertical field of view, circle of confusion (Zeiss d/1500 standard), and full depth-of-field tables for your exact sensor dimensions. It approximates optical behavior assuming rectilinear lenses and thin-lens geometry.

Formulas

The crop factor is derived from the ratio of sensor diagonals. The full-frame reference diagonal is √36² + 24² = 43.27 mm.

CF = d_ffd_sensor

where d_sensor = √w² + h².

Equivalent focal length and equivalent aperture scale linearly with crop factor:

EFL = f × CF

EA = N × CF

Horizontal field of view uses the arctangent relation:

FOV_h = 2 ⋅ arctan(w2 ⋅ f)

Circle of confusion follows the Zeiss standard:

CoC = d_sensor1500

Hyperfocal distance determines the depth-of-field boundaries:

H = f²N ⋅ CoC + f

D_near = s ⋅ (H − f)H + s − 2f

D_far = s ⋅ (H − f)H − s

where f = actual focal length, N = f-number (aperture), s = subject distance, w = sensor width, h = sensor height, d_ff = full-frame diagonal (43.27 mm), H = hyperfocal distance. When s ≥ H, the far limit extends to infinity.

Reference Data

Sensor Format	Width mm	Height mm	Diagonal mm	Crop Factor	CoC mm
Medium Format (Fuji GFX)	43.8	32.9	54.78	0.79	0.037
Full Frame (35mm)	36.0	24.0	43.27	1.00	0.029
APS-H (Canon)	28.7	19.0	34.42	1.26	0.023
APS-C (Canon)	22.3	14.9	26.82	1.61	0.019
APS-C (Nikon/Sony/Fuji)	23.5	15.6	28.21	1.53	0.019
APS-C (Sigma Foveon)	20.7	13.8	24.88	1.74	0.017
Micro Four Thirds	17.3	13.0	21.64	2.00	0.015
Nikon CX (1")	13.2	8.8	15.86	2.73	0.011
1" Sensor (Sony RX100)	13.2	8.8	15.86	2.73	0.011
1/1.7" Compact	7.6	5.7	9.50	4.55	0.006
1/2.3" Compact	6.17	4.55	7.67	5.64	0.005
1/2.5" Action Cam	5.76	4.29	7.18	6.02	0.005
iPhone 15 Pro Main	9.8	7.3	12.22	3.54	0.008
Super 35mm (Cinema)	24.89	18.66	31.11	1.39	0.021
RED Komodo (S35)	27.03	14.26	30.56	1.42	0.020
ARRI Alexa LF	36.70	25.54	44.71	0.97	0.030
Hasselblad X2D	43.8	32.9	54.78	0.79	0.037
Phase One IQ4 (645)	53.4	40.0	66.73	0.65	0.044
Samsung Galaxy S24 Ultra	10.0	7.5	12.50	3.46	0.008
DJI Mavic 3 (4/3")	17.3	13.0	21.64	2.00	0.015

Frequently Asked Questions

No. A 50 mm lens has a 50 mm focal length regardless of the sensor behind it. Crop factor describes how the sensor crops the image circle, producing a narrower field of view equivalent to a longer focal length on full frame. The optical properties (aberrations, light-gathering, perspective compression at a given distance) remain unchanged.

Exposure depends on the light intensity per unit area reaching the sensor, which is controlled by the physical f-number alone. A lens at f/2.8 delivers the same exposure on any sensor size. Depth of field, however, depends on magnification. A smaller sensor requires less magnification (or a shorter focal length for the same framing), which increases apparent depth of field. Multiplying the f-number by the crop factor gives the full-frame aperture that would produce similar depth of field and background blur.

The Zeiss formula divides the sensor diagonal by 1500, yielding approximately 0.029 mm for full frame. Some references use d/1000 (looser, yields 0.043 mm) or fixed values like 0.025 mm. The d/1500 standard assumes a print size of roughly 25 cm viewed at 25 cm distance. For large prints or pixel-peeping on high-resolution sensors, you may want a stricter CoC (d/2000 or smaller). This calculator uses d/1500 as the industry baseline.

Yes. Medium format sensors (e.g., Fuji GFX at 43.8 × 32.9 mm, Phase One at 53.4 × 40.0 mm) have diagonals larger than the 43.27 mm full-frame reference, producing crop factors of 0.79 and 0.65 respectively. This means they capture a wider field of view than full frame at the same focal length.

A smaller sensor has a smaller circle of confusion and typically uses a shorter focal length for equivalent framing. These two effects partially cancel, but not entirely. For the same field of view and equivalent aperture, a crop sensor's hyperfocal distance is shorter by a factor of approximately 1/CF. This gives crop sensors a practical advantage for deep-focus landscape work at equivalent compositions.

A 0.71× speed booster on an APS-C body (CF 1.5) reduces the effective crop to approximately 1.5 × 0.71 ≈ 1.07, close to full frame. It compresses the full-frame image circle onto the smaller sensor, recovering roughly one stop of light and the original field of view. However, optical quality depends on the adapter; cheap units introduce aberrations at wide apertures.