Below is an overview of how different focal lengths and aperture values compare between fullframe, APS-C (both general and Canon-specific), micro 4/3 and medium format. These tables will help you quickly see which lens on your camera gives a similar angle of view or depth of field as on a full-frame camera.
The first table shows the conversion factors for each sensor format. The second and third tables respectively show the converted focal lengths and aperture values based on a fullframe reference.
The differences arise from the difference in sensor size:
| Sensor size | |
| Fullframe | 36 mm by 24 mm |
| APS-C | 23.6 mm by 15.8 mm |
| Micro 4/3 | 17.3 mm by 13 mm |
| Medium format | 43.8 mm x 32.9 mm |
If we assume fullframe, calculate the other focal lengths as follows:
| Sensor | Conversion factor to fullframe | Example |
| Fullframe | 1 | 35mm fullframe |
| APS-C | 1,5 | 23mm APS-C is 35mm fullframe |
| Micro 4/3 | 2 | 17mm Micro 4/3 is 35mm fullframe |
| Medium format | 0,79 | 45mm medium format is 36mm fullframe |
Focal length conversion table to fullframe in mm
In the table below, I have assumed the Fujifilm X (APS-C) and GFX (medium format) focal lengths (existing lenses) and the OM System (micro 4/3) focal lengths (existing lenses).
| Fullframe | APS-C | Micro 4/3 | Medium format |
| 12 | 8 | ||
| 14 | 7 | ||
| 15 | 10 | ||
| 16 | 8 | 20 | |
| 18 | 9 | 23 | |
| 21 | 14 | ||
| 23 | 15 | ||
| 24 | 16 | 12 | 30 |
| 25 | 32 | ||
| 27 | 18 | ||
| 28 | 14 | 35 | |
| 35 | 23 | 17 | |
| 36 | 18 | 45 | |
| 40 | 27 | 20 | 50 |
| 43 | 55 | ||
| 45 | 30 | ||
| 50 | 33 | 25 | 63 |
| 51 | 64 | ||
| 53 | 35 | ||
| 55 | 70 | ||
| 63 | 80 | ||
| 68 | 45 | ||
| 75 | 50 | ||
| 79 | 100 | ||
| 80 | 40 | ||
| 83 | 55 | ||
| 84 | 56 | 42 | |
| 87 | 110 | ||
| 90 | 60 | 45 | |
| 95 | 120 | ||
| 105 | 70 | ||
| 120 | 80 | 60 | |
| 135 | 90 | ||
| 150 | 75 | ||
| 158 | 200 | ||
| 180 | 120 | 90 | |
| 200 | 135 | 100 | 250 |
| 210 | 140 | ||
| 225 | 150 | ||
| 300 | 200 | 150 | |
| 345 | 230 | ||
| 395 | 500 | ||
| 450 | 300 | ||
| 600 | 400 | 300 | |
| 750 | 500 | ||
| 800 | 400 | ||
| 900 | 600 | ||
| 1.200 | 600 |
Conversion table aperture number (f-number) to fullframe
Each step to a higher number (e.g. from f/2.0 to f/2.8) means the lens lets in half as much light. Conversely (from f/8 to f/5.6) means twice as much light.
The ratio between them is based on powers of √2 (about 1.41), because the aperture area increases or decreases in area per doubling/halving of light incidence.
In the table below, the full stops are shown in bold.
Note that an aperture of f/2.8 always remains an aperture of 2.8, no matter what system you use. The aperture value itself does not change when you use a lens on a crop camera, but the effects of that aperture - particularly the depth of field and background blur (bokeh) - do change. That's where the aperture conversion factor comes in.
| Fullframe | APS-C | Micro 4/3 | Medium format |
| 0.8 | 1.0 | ||
| 0.9 | 1.2 | ||
| 1.0 | |||
| 1.1 | 1.4 | ||
| 1.2 | |||
| 1.4 | 1.8 | ||
| 1.5 | 1.0 | ||
| 1.6 | 2.0 | ||
| 1.8 | 1.2 | ||
| 2.0 | 1.0 | 2.5 | |
| 2.1 | 1.4 | ||
| 2.2 | 2.8 | ||
| 2.4 | 1.2 | ||
| 2.5 | 3.2 | ||
| 2.7 | 1.8 | ||
| 2.8 | 1.4 | ||
| 3.0 | 2.0 | ||
| 3.2 | 4.0 | ||
| 3.5 | |||
| 3.6 | 1.8 | 4.5 | |
| 3.8 | 2.5 | ||
| 4.0 | 2.0 | 5.0 | |
| 4.2 | 2.8 | ||
| 4.4 | 5.6 | ||
| 4.5 | |||
| 4.8 | 3.2 | ||
| 5.0 | 2.5 | ||
| 5.1 | 6.4 | ||
| 5.6 | 2.8 | 71 | |
| 6.0 | 4.0 | ||
| 6.3 | 8.0 | ||
| 6.4 | 3.2 | ||
| 6.8 | 4.5 | ||
| 7.1 | 9.0 | ||
| 7.5 | 5.0 | ||
| 8.0 | 4.0 | ||
| 8.4 | 5.6 | ||
| 8.7 | 11.0 | ||
| 9.0 | 4.5 | ||
| 9.6 | 6.4 | ||
| 10.0 | 5.0 | ||
| 10.7 | 7.1 | ||
| 11.0 | |||
| 11.2 | 5.6 | ||
| 12.0 | 8.0 | ||
| 12.6 | 16.0 | ||
| 12.8 | 6.4 | ||
| 13.0 | |||
| 13.5 | 9.0 | ||
| 14.0 | |||
| 14.2 | 7.1 | ||
| 16.0 | 8.0 | ||
| 16.5 | 11.0 | ||
| 17.4 | 22.0 | ||
| 18.0 | 9.0 | ||
| 22.0 | 11.0 | ||
| 24.0 | 16.0 | ||
| 25.3 | 32.0 | ||
| 32.0 | 16.0 | ||
| 33.0 | 22.0 | ||
| 44.0 | 22.0 | ||
| 48.0 | 32.0 | ||
| 64.0 | 32.0 |
All numbers on this page approximate.