Convert focal length and aperture between Full Frame, APS-C Canon (1.6x), Sony/Nikon APS-C (1.5x), Micro Four Thirds, 1-inch, Fuji GFX and Phase One sensors.
Built and maintained by Paul Clark, Redmoon Software · Checked against what this tool computes on
| Sensor | Crop | Equivalent focal (mm) | Equivalent aperture (DOF) |
|---|
Field of view scales with the crop factor: equivalent focal = focal × (source crop / target crop). Depth of field scales the same way: equivalent aperture = aperture × (source crop / target crop). Exposure is unchanged — an f/2.8 lens still meters at f/2.8 on any sensor.
Crop factors are relative to a 36×24 mm full-frame sensor (diagonal ≈ 43.27 mm).
Two multiplications drive the whole tool: equivalent focal length = focal length x (source crop factor / target crop factor), and equivalent aperture = f-number x that same ratio. The headline result converts your lens to its full-frame equivalent, and the table underneath repeats the calculation against all seven sensors at once. Crop factors are ratios of sensor diagonal to full frame's 43.27 mm, so Micro Four Thirds at 2.0x sees half the field of view.
Set Source sensor first. The dropdown runs Phase One IQ4 (0.64x), Fuji GFX 50/100 (0.79x), Full Frame (1.0x), APS-C Nikon / Sony (1.5x), APS-C Canon (1.6x), Micro Four Thirds (2.0x) and 1-inch (2.7x). Focal length and aperture default to 50 mm and f/1.8, and six preset buttons load 24 mm f/1.4 through 200 mm f/2.8. The row matching your source sensor is highlighted in the comparison table.
The equivalent aperture column describes depth of field and total light gathered, not exposure. An f/1.8 lens still meters at f/1.8 on every sensor, so never dial the equivalent number into your camera. The tool also uses nominal crop factors rather than each body's exact sensor dimensions, ignores the aspect-ratio differences between formats such as 4:3 Micro Four Thirds against 3:2 full frame, and says nothing about noise differences between sensor sizes.
With APS-C Canon (1.6x) selected, a 50 mm f/1.8 reports as 80 mm at f/2.88 full-frame equivalent. On Nikon or Sony APS-C at 1.5x the same lens reports 75 mm at f/2.70. The framing and background blur change; the physical lens does not.
Depth of field depends on the physical diameter of the aperture relative to the format. Multiplying the f-number by the crop factor gives the full-frame f-number that would produce the same depth of field and collect the same total light across the frame.
No. Exposure is set by f-number, shutter speed and ISO regardless of sensor size, and the tool never adjusts your metering. The equivalent aperture figure exists purely to compare background blur and total light between different formats.
The tool uses 2.0x, so a 25 mm Micro Four Thirds lens frames like 50 mm on full frame. One-inch sensors are 2.7x. Medium format goes the other way: Fuji GFX is 0.79x and Phase One IQ4 is 0.64x, values below 1.0 that widen rather than crop.
Yes. Set Source sensor to the format you shoot, then read the row for the format you want to compare against. Because the table divides by the target's crop factor, Micro Four Thirds to APS-C Canon works without going through full frame first.
Crop factor is the ratio of a sensor's diagonal to full frame — 1.5 for most APS-C, 1.6 for Canon APS-C, 2.0 for Micro Four Thirds, 2.7 for 1-inch, and below 1.0 for medium format. Multiplying focal length by it gives the full-frame focal length with the same field of view.
It applies to field of view and, for an equivalent framing, to depth of field. It does not apply to exposure: an f/2.8 lens is f/2.8 on any sensor, and the shutter speed and ISO that expose correctly do not change with format.
The depth-of-field part is where discussion goes wrong. At the same focal length and aperture, depth of field is essentially the same regardless of sensor — but you are standing somewhere else to get the same framing, and that is what changes it. Framed identically, a smaller sensor gives more depth of field at the same f-number.
The same logic applies to total light gathered: a smaller sensor at the same f-number collects less total light across its area, which is why noise performance differs between formats at matched settings even though exposure does not.
For practical purposes: use crop factor to choose a lens that frames what you want, and treat aperture as an exposure setting that also has a depth-of-field consequence you judge on the sensor you are actually using.
The standard or formula behind this tool, so you can check it rather than take it on trust.
Crop factor applies to field of view and to depth of field — not to exposure.
An f/2.8 lens is f/2.8 on any sensor. What changes is the framing, and the depth of field for an equivalent framing.
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