Focal length equivalents

MFT APS‑C FF MF
12mm 16mm 24mm 30mm
13mm 18mm 27mm 35mm
18mm 23mm 35mm 45mm
20mm 27mm 40mm 50mm
25–27mm 33–35mm 50mm 63mm
42mm 56mm 85mm 105mm
68mm 90mm 135mm 170mm

Table of relationship between various photographic parameters

ALL OTHER PARAMETERS BEING EQUAL – e.g., effect of focal length assumes that aperture ratio stays constant, not the physical diameter of the lens!

dependent ╲ independent exposure flash exposure field of view bokeh diameter depth of field subject motion blur camera motion blur film grain / quantization noise image noise resolution
focal length (mm) −1 2 −2
aperture (f) −2 −2 −1
shutter speed (1s) −1
sensitivity (ISO)
push processing (ISO)
sensor size (diag) −1 −1 −1 −2
pixel count
cropping (diag) −1 −1 −2
scaling
image stabilization −1
ND filter −1 −1
flash power