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In the single-lens reflex camera the photographer sees the scene through the camera lens.

This avoids the problem of parallax which occurs when the viewfinder or viewing lens is separated from the taking lens.

Single-lens reflex cameras have been made in several formats including 220 / 120 taking 8, 12 or 16 photographs on a 120 roll and twice that number of a 220 film.

These correspond to 6x9, 6x6 and 6x4. 5 respectively ( all dimensions in cm ).

Notable manufacturers of large format SLR include Hasselblad, Mamiya, Bronica and Pentax.

However the most common format of SLRs has been 35 mm and subsequently the migration to digital SLRs, using almost identical sized bodies and sometimes using the same lens systems.