Welcome to this quick-fire guide to understanding your camera’s crop factor and how it affects your photos. If you don’t have a lot of time right now, simply download the PDF version of this guide to read offline.
What is a Crop Factor?
All digital cameras that don’t have a full-frame sensor are referred to as cropped sensors. It means they are smaller than a full-sized one. This difference in size will reflect a difference in your photographs.
The size of your camera’s sensor will change the focal length of any lens you use. For example, a 50mm lens will never be truly 50mm on a cropped sensor.
Common Crop Factors
1.29x crop factor for APS-H Sensors (Canon)
1.52x crop factor for APS-C Sensors (Other Brands)
1.61x crop factor for APS-C Sensors (Canon)
2.0x crop factor for Micro 4/3rd Cameras
2.72x crop factor for Compact Cameras
How to Work Out Crop Factor
To work out your crop factor and how it changes your focal length simply multiply
FOCAL LENGTH X FORM FACTOR
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Examples of Crop Factor in Practise
50mm (focal length) x 1.29 (crop factor) = 64.5mm (equivalent focal length to 35mm/full frame)
85mm (focal length) x 1.52 (crop factor) = 129.2mm (equivalent focal length to 35mm/full frame)
100mm (focal length) x 2.0 (crop factor) = 200mm (equivalent focal length to 35mm/full frame)
Crop Factor Applies to Zoom Lenses Too
The same goes for zoom lenses. If you have a standard kit lens (18-55mm) on an entry level DSLR camera (APS-C sized sensor) the once crop factor is applied that lens will actually be giving you equivalent focal lengths of between 27.36-83.6mm lens
