Crop Factor Calculator: Full-Frame Lens Equivalents

Sensor	Crop	Equiv. FL	Equiv. aperture	Equiv. ISO	FoV (H)
Medium Format (Fuji GFX)	0.79×	40 mm	f/1.4	ISO 62	47.3°
Medium Format (Hasselblad)	0.79×	40 mm	f/1.4	ISO 62	47.3°
Full Frame (35 mm)	1×	50 mm	f/1.8	ISO 100	39.6°
APS-C (Nikon / Sony / Pentax)	1.5×	75 mm	f/2.7	ISO 225	26.4°
APS-C (Canon)	1.6×	80 mm	f/2.9	ISO 256	25.1°
APS-C (Sigma Foveon)	1.7×	85 mm	f/3.1	ISO 289	23.4°
Micro Four Thirds	2×	100 mm	f/3.6	ISO 400	19.6°
1" Sensor	2.7×	135 mm	f/4.9	ISO 729	15.0°
1/1.7" Sensor	4.55×	228 mm	f/8.2	ISO 2,070	8.7°
1/2.3" Sensor (compact / phone)	5.6×	280 mm	f/10	ISO 3,136	7.1°

Crop Factor Calculator: 35 mm Equivalents Explained

A 50 mm lens on APS-C is not the same picture as 50 mm on full frame. Here is how to read the 35 mm equivalents for framing, background blur, and noise without guessing.

What this calculator does

A 50 mm lens does not frame the same on APS-C and full frame. Enter your sensor, focal length, aperture, and ISO and the panel translates them into full-frame framing, DoF, and noise equivalents, with horizontal field of view in degrees. The comparison table lines up every preset format on one focal length so you can shop or pack a bag without mental math.

How the Math Works

All conversions use the crop factor, which is derived from sensor dimensions:

Crop factor:

$\text{Crop factor} = \frac{d_{\text{ff}}}{d_{\text{sensor}}}$
where $d_{\text{ff}} = \sqrt{36^2 + 24^2} \approx 43.27\,\text{mm}$ is the full-frame diagonal and $d_{\text{sensor}}$ is your sensor's diagonal.
Equivalent focal length:

$\text{FL}_{\text{eq}} = \text{FL}_{\text{actual}} \times \text{crop factor}$
Example: 50 mm on APS-C Nikon (1.5×): $50 \times 1.5 = 75\,\text{mm}$ equivalent.
Equivalent aperture (depth of field):

$f_{\text{eq}} = f_{\text{actual}} \times \text{crop factor}$
This does not affect exposure. It describes the full-frame aperture that gives the same depth of field at the equivalent focal length and framing distance. Example: f/1.8 on 1.5×: $1.8 \times 1.5 = f/2.7$ equivalent DoF.
Equivalent ISO (noise):

$\text{ISO}_{\text{eq}} = \text{ISO}_{\text{actual}} \times \text{crop factor}^2$
A smaller sensor gathers less total light at the same settings and framing. Example: ISO 100 on 1.5×: $100 \times 1.5^2 = 225$ , so noise is comparable to ISO 225 on full frame.
Field of view:

$\text{FoV} = 2 \times \arctan\!\left(\frac{w}{2 \times \text{FL}}\right)$
where w is the sensor width (or height for vertical FoV). A narrower sensor produces a narrower field of view, giving the telephoto "reach" effect. FoV uses measured sensor dimensions; equivalent focal length uses rounded crop factors, so the mm equivalent and the angle may not line up to the last millimeter on APS-C.

Why crop factor matters when buying lenses

Lens catalogs list focal length in millimeters, but the same number frames very differently on APS-C versus full frame. Match the format before you compare prices.

Buying a portrait lens for APS-C:

On full frame, the classic portrait focal length is 85 mm. On a 1.5× APS-C body, a 56 mm lens gives similar framing (56 × 1.5 = 84 mm equivalent). An actual 85 mm lens on APS-C frames like 127 mm, which is tighter than most people want for head-and-shoulders portraits.
Wildlife and sports (crop advantage):

A 200 mm f/2.8 on Micro Four Thirds (2×) frames like a 400 mm f/5.6 on full frame. You get the reach of a much longer, heavier, and more expensive full-frame lens. The trade-off is shallower depth of field control and more noise at high ISO.
Landscape and wide angle:

Wide-angle lenses lose their wide perspective on crop sensors. A 16 mm lens on a 1.6× Canon APS-C sensor frames like 25.6 mm on full frame, which is a normal-wide, not ultra-wide. To get a true ultra-wide view on crop, you need a lens like 10 mm or 12 mm.
Depth of field comparison:

If shallow background blur is important, compare the equivalent aperture, not just the f-number on the lens. f/1.4 on Micro Four Thirds (2×) gives the same DoF as f/2.8 on full frame. To match the full-frame f/1.4 look, you would need f/0.7, which does not exist for that mount.

Common Crop Factors by Camera System

Canon APS-C is 1.6× while Nikon and Sony APS-C sit at 1.5×; that small gap changes equivalent reach. Diagonal-based crop factors for common systems:

Medium Format (Fuji GFX, Hasselblad X):

0.79× crop. Sensor is 43.8 × 32.9 mm, larger than full frame. More background blur at the same f-stop and wider angle per focal length than 35 mm full frame.
Full Frame (35 mm):

1.0× (reference standard). Sensor is 36 × 24 mm. Lens focal lengths and apertures match their marked values directly. Canon R, Nikon Z, Sony A7, Panasonic S, Leica SL.
APS-C (Nikon, Sony, Fuji, Pentax):

1.5× crop. Sensor is approximately 23.5 × 15.6 mm. The most common crop format. A 35 mm lens frames like 52.5 mm on full frame.
APS-C (Canon):

1.6× crop. Sensor is 22.3 × 14.9 mm, slightly smaller than other APS-C sensors. Canon EOS R7, R10, R50, and older EF-S DSLRs (7D, 80D, Rebel series). The Canon crop factor of 1.6× means a 50 mm lens frames like 80 mm on full frame, and a popular Canon EF-S 10–18 mm wide-angle zoom gives a 16–29 mm equivalent range.
Micro Four Thirds (Olympus/OM System, Panasonic):

2.0× crop. Sensor is 17.3 × 13.0 mm. Popular for video and wildlife due to the effective 2× reach multiplier and compact body/lens size.
1" Sensor (Sony RX100, Nikon 1):

2.7× crop. Sensor is 13.2 × 8.8 mm. Found in premium compact cameras and some drones.

FAQ

What is crop factor in photography?

Divide the 35 mm full-frame sensor diagonal (about 43.27 mm) by your camera sensor's diagonal. APS-C at 1.5× has a sensor about 1.5 times smaller than full frame, so a 50 mm lens frames like 75 mm would on full frame. Crop factor describes framing, not a change to the glass itself.

How do I calculate equivalent focal length from crop factor?

Multiply the actual focal length of the lens by the crop factor. A 50 mm lens on a 1.5× APS-C sensor gives a 35 mm equivalent of 75 mm (50 × 1.5). This tells you the full-frame lens that would produce the same field of view. The lens optics don't change; only the framing narrows because the smaller sensor crops the image circle.

Does crop factor affect aperture or depth of field?

Crop factor does not change the physical aperture of the lens or the amount of light it transmits. However, to get the same framing on a crop sensor you stand at the same distance, and the smaller sensor captures a narrower slice. The equivalent aperture for depth-of-field comparison is the actual aperture multiplied by the crop factor. A 50 mm f/1.8 on a 1.5× sensor gives roughly the same DoF as a 75 mm f/2.7 on full frame.

Does crop factor affect ISO noise?

Crop factor itself does not change ISO noise directly. But a smaller sensor collects less total light for the same exposure settings and framing. To compare noise between sensors at the same field of view and depth of field, multiply ISO by the crop factor squared. ISO 100 on a 1.5× APS-C sensor is roughly equivalent to ISO 225 on full frame in terms of noise.

What is the crop factor of APS-C, Micro Four Thirds, and other sensors?

Common crop factors: Full Frame = 1.0×, APS-C (Nikon/Sony) = 1.5×, APS-C (Canon) = 1.6×, Micro Four Thirds = 2.0×, 1" sensor = 2.7×, 1/2.3" sensor (compact cameras, phones) = 5.6×. Medium format sensors like the Fuji GFX have a crop factor less than 1 (about 0.79×) because they are larger than 35 mm.

Is a higher or lower crop factor better for photography?

It depends on what you shoot. A lower crop factor (larger sensor) collects more light, produces shallower depth of field, and generally has less noise at high ISO, which benefits portraits and low-light work. A higher crop factor (smaller sensor) gives more "reach" at the same focal length, useful for wildlife and sports where getting closer is not an option. There is no universally better value; each format has trade-offs.

How does field of view relate to crop factor?

Field of view narrows as crop factor increases. The horizontal field of view is calculated as 2 × arctan(sensor width / (2 × focal length)). A 50 mm lens on full frame gives about 39.6° horizontal FoV. The same lens on a 1.5× APS-C sensor (23.5 mm wide) gives about 26°, and on a 2.0× Micro Four Thirds sensor about 19.6°.

Does crop factor change the actual focal length of a lens?

No. A 50 mm lens is always a 50 mm lens regardless of the sensor behind it. Crop factor describes how the sensor frames the image, not the optical properties of the lens. The term "equivalent focal length" is a shorthand for the full-frame focal length that would give the same field of view.

What is the Canon crop factor and how does it differ from Nikon or Sony?

Canon APS-C cameras (EOS R7, R10, R50, older Rebels and XXD bodies) use a 1.6× crop factor, while Nikon, Sony, Fuji, and Pentax APS-C cameras use 1.5×. The difference is small but real: a 50 mm lens on Canon APS-C gives an 80 mm equivalent, while the same lens on Nikon or Sony APS-C gives 75 mm. Canon's slightly smaller sensor also narrows the field of view a bit more and produces marginally higher equivalent ISO noise at the same settings.

Crop Factor Calculator: What's the Full-Frame Equivalent of Your Lens?