Sensor Comparison Calculator
Compare two sensor formats by crop factor and surface area.
Results
- Sensor A crop factor (vs. full frame)
- 1.00x
- Sensor B crop factor (vs. full frame)
- 2.00x
- B relative to A
- 2.00x
- Sensor area difference
- 3.84× larger (Sensor A)
How much narrower Sensor A's field of view is compared to a 36×24mm full-frame sensor, at the same focal length.
How much narrower Sensor B's field of view is compared to a 36×24mm full-frame sensor, at the same focal length.
How much narrower Sensor B's field of view is compared to Sensor A, at the same focal length.
Sensor A has the greater surface area, collecting about 1.9 stops more light in total across the frame. This roughly tracks with noise performance at a matched field of view.
How it works
Crop factor is the ratio of the full-frame diagonal to a given sensor's diagonal. It tells you how much narrower the same lens will look on that sensor, and it is the number that lets photographers translate between formats.
Sensor area matters for a different reason. A larger sensor collects more total light at a matched field of view and exposure, and that extra light is what produces cleaner shadows and more usable high-ISO files. The difference expressed in stops is often more revealing than the raw ratio: full frame holds roughly a two-stop advantage over Micro Four Thirds.
Neither figure tells the whole story. Sensor generation, pixel design, and readout electronics routinely close gaps that raw area suggests should exist, and a modern APS-C sensor will comfortably beat a decade-old full-frame one.
The formula
crop factor = 43.27 / sensor diagonal, area difference in stops = log₂(area ratio)
43.27mm is the diagonal of a 36×24mm full-frame sensor. Crop factor is derived from diagonals, not from width or area.
Frequently asked questions
- Does crop factor change my lens's aperture?
- Not for exposure. An f/2.8 lens gathers f/2.8 worth of light per unit area on any sensor. What changes is depth of field and total light collected across the whole frame, which is what the equivalent aperture figure describes.
- Why is crop factor measured on the diagonal?
- Because the diagonal is the only dimension that behaves consistently when aspect ratios differ. Using width alone would give misleading results comparing a 3:2 sensor with a 4:3 one.
- Is a bigger sensor always better?
- Not for every purpose. Larger sensors mean larger, heavier, more expensive lenses and less depth of field, which is a drawback for macro and wildlife work where depth is scarce and reach is valuable.