Depth of field / sensor size

Technically, the depth of field produced by a lens does not vary according to the size of a camera’s image sensor. However, in practice, there is a difference.

Imagine you are taking the same image, with the same aperture and lens, using a camera with an APS-C size sensor and a camera with a full-frame sensor. If you take a shot from the same place, the depth of field will be identical, but the resulting images will not.

To match the image taken with the full-frame camera, the shot with the APS-C-sensor camera must be taken from further away to account for the 1.5x focal length increase. This, in turn, produces a greater depth of field when compared to the full-frame image, even though the images are taken at identical focal lengths and apertures. Basically, the closer you are to a subject, the shallower the depth of field becomes – as shown in macro images.

To take things further, the aperture of a lens is relative to its focal length. For example, an aperture of f/2.8 in a full-frame lens is a lot larger than the physically smaller aperture of f/2.8 in a compact camera lens. This means that the compact camera has a larger depth of field.

For more information, including the formula for calculating depth of field, see Depth of field explained

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