With this brief article I do not want to explain anything difficult but just show how different the usual formats of films and sensors are. These are the most common ones. 

common formats


  Format Measures in mm Factor
1 Medium Format 6x7 60x70 0,47
2 Medium Format 4,5x6 45x60 0,57
3 Digital MF 36x46 0,74
4 Small Film 1) 24x36 1
5 DX 15.6x23.7  1.5
6 APS-C 2) 14.8x22.2  1.62
7 Foveon 13.8x20.7   
8 M4/3 3) 13x17.3  2
9 1" 8.8x13.2  2.7
10 2/3" 6.6x8.8  3.92
11 1/1.8" 5.4x7.2  4.81
12 1/2.5" 4.3x5.8  6
13 1/2.7" 4x5.4  6.43
14 1/3.2" 3.4x4.5  7.67


1) Small film relates to the standard 24x36 on 135 type film. On film there other rather exotic formats too, such as 57x24 for panoramic formats, half format of 18x24 or even more exotic ones. For DSLR we usually refer to the full frame (full format) FF. 

2) APS-C is a film format which varies slightly from the quasi APS-C that Canon, Sigma, Sony and Nikon uses. The difference to Canon APS-C is so small that I did not find it of being much of a value to include the real film APS-C in the graphic. 

3) M4/3 ist an equivalent of Micro Four Thirds. This is the same sensor size as FT (Four Thirds) and happens to be the same frame size as used on 110 film.