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Chapter 3 Lenses
Figure 3-19. If the digital camera you use has a sensor that is smaller than a 35 mm frame, then there is a
crop factor for that camera.
Full frame (24 × 36 mm)
APS-C (18 × 24 mm)
APS-C (Nikon DX, Pentax, Sony) 1.5X
APS-C (Canon) 1.6X
Foveon (Sigma) 1.7X
Full frame (35mm)
APS-H (Canon) 1.3X
Four thirds 2.0X
Figure 3-20. Multiply the crop factor by the focal length of the lens to fi nd the true focal length of your lens and
camera combination.