Sensors Equipping Most DSLRs and Mirrorless Interchangeable-lens Cameras
Most consumer-level DSLRs and MILCs/EVILs use relatively large sensors, either around the size of a frame of APS-C film, with a crop factor of 1.5-1.6; or 30% smaller than that, with a crop factor of 2.0 (this is the Four Thirds System, adopted by Olympus and Panasonic).
On September 2011, Nikon announced their new format CX, whose size is 1" (2.7 crop factor). It has been adopted for the Nikon 1 camera system (Nikon J1 and V1 models). As of September 2011 there is only one MILC model equipped with a very small sensor, typical of compact cameras: it is the Pentax Q, equipped with a 1/2.3" sensor (5.62 crop factor). See Sensors equipping Compact digital cameras and camera-phones section below.
Many different terms are used in marketing to describe DSRL/MILC sensor formats, including the following:
- Full-frame digital SLR format, with sensor dimensions nearly equal to those of 35 mm film (36 × 24 mm)
- Canon's APS-H format for high-speed pro-level DSLRs (crop factor 1.3)
- Leica's M8 and M8.2 sensor (crop factor 1.33).
- APS-C refers to a range of similarly-sized formats, including
- Nikon, Pentax, Samsung, Konica Minolta/Sony, Fujifilm, Epson, Sigma (crop factor 1.5)
- Canon entry-level DSLR formats (crop factor 1.6)
- Foveon X3 format used in Sigma SD-series DSLRs and DP-series mirrorless (crop factor 1.7) (latest models include SD1, DP2 Merrill use crop factor 1.5 foveon sensor)
- Four Thirds System and Micro Four Thirds System format (crop factor 2.0)
- Nikon CX format used in Nikon 1 series (crop factor 2.7)
When full-frame sensors were first introduced, production costs could exceed twenty times the cost of an APS-C sensor. Only about thirty full-frame sensors can be produced on an 8 inches (20 cm) silicon wafer that would fit 112 APS-C sensors, and there is a significant reduction in yield due to the large area for contaminants per component. Additionally, the full frame sensor originally required three separate exposures during the photolithography stage, which requires separate masks and quality control steps. The APS-H size was selected since it was then the largest that could be imaged with a single mask to help control production costs and manage yields. Newer photolithography equipment now allows single-pass exposures for full-frame sensors, although other size-related production constraints remain much the same.
Due to the ever-changing constraints of semiconductor fabrication and processing, and because camera manufacturers often source sensors from third-parties foundries, it is common for sensor dimensions to vary slightly within the same nominal format. For example, the Nikon D3 and D700 cameras' nominally full-frame sensors actually measure 36 × 23.9 mm, slightly smaller than a 36 × 24 mm frame of 35 mm film. As another example, the Pentax K200D's sensor (made by Sony) measures 23.5 × 15.7 mm, while the contemporaneous K20D's sensor (made by Samsung) measures 23.4 × 15.6 mm.
Most DSLR image sensor formats approximate the 3:2 aspect ratio of 35 mm film. Again, the Four Thirds System is a notable exception, with an aspect ratio of 4:3 as seen in most compact digital cameras (see below).
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