APS-C
From Wikipedia, the free encyclopedia
Advanced Photo System type-C (APS-C) is a designation sometimes given to digital sensors that are approximately equivalent in size to the Advanced Photo System "classic" size negatives. These negatives were 25.1 x 16.7 mm and had an aspect ratio 3:2.
Sensors meeting these approximate dimensions are used in many digital single-lens reflex cameras, in addition to a few large-sensored live-preview digital cameras (such as the Sony DSC-R1 and the Sigma DP1) and a few digital rangefinders (e.g. the Epson R-D1). Such sensors exist in many different variants depending on the manufacturer and camera model[1]. All APS-C variants are considerably smaller than 35 mm standard film which measures 36×24 mm. Sensor sizes range from 20.7×13.8 mm to 28.7×19.1 mm. Each variant results in a slightly different field of view (FOV) from lenses at the same focal length and overall a much narrower field of view compared to 35 mm film.
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[edit] Brand Designations
Most DSLR and 3rd party lens manufacturers now make lenses specifically designed for APS-C cameras. The designations by brand include:
[edit] Multiplier factors
A focal length multiplier (FLM) also known as a "crop factor" can be used to calculate the 35 mm equivalent focal length from the actual focal length. The most common multiplier ratios (in order of announcements):
- 1.6× — Canon EOS 400D, Canon EOS 30D, Canon EOS 20Da, Canon EOS 350D, Canon EOS 20D*, Canon EOS 300D*, Canon EOS 10D*, Canon EOS D60*, Canon EOS D30*
- 1.5× — all Nikon DSLR, all Fuji DSLR (Fuji uses Nikon bodies), Sony DSLR-A100 (with technology from Konica Minolta), Konica Minolta Maxxum 5D*, Konica Minolta Maxxum 7D*, All Pentax DSLR
- 1.3× — Canon EOS-1D Mark II N, Canon EOS-1D Mark II*, Canon EOS-1D*
(* discontinued)
[edit] Lens differences, incompatibilities
Lenses with 1.6× multiplier — also called crop — such as the Canon EF-S line, place the rear of the lens closer to the camera's sensor (referred to as Short Back Focus). This has several benefits, including increasing the focal range. It also has downsides, in that the lenses aren't compatible with camera bodies that use a full-size mirror, as it would damage the mirror, and thus the lenses can't be used on other digital or analog bodies.
Cameras capable of using short-back lenses include the Canon EOS 300D and 350D — also known as Digital Rebel and Digital Rebel XT; and more recently the EOS 400D, also known as the digital Rebel XTi — as well as the 20D and its latest successor, the 30D. These cameras support conventional 35 mm lenses as well.
