Definition: Lens designation; Lens Marques; Full Frame designation; APS-C designation; Brand lens designation;
Lenses are matched to a specific camera mount – they will not fit a camera for which they are not designed. The specifications and mount types are available on the manufacturers websites. You should also check that the lens designation marks the lenses which are suitable to the type of sensor you have. The Lens designation tells you if you have a compatible lens-camera match.
Cameras generally have a full frame sensor, or a cropped sensor. (See also: Digital image sensor)
Full frame sensors
Full frame sensors are classed as 35mm equivalent size after original film sizes from the days of SLR cameras. The specific size of the full frame sensor is 36mm x 24mm (aspect ratio 3:2). This was the size of an individual negative film frame on a roll of film. Full frame sensors require that the lens projects an image circle onto the sensor that completely covers the sensor array of pixels.
APS-C (cropped) sensors
A smaller film format was also in common use along side 35mm. The Advanced Photo System type-C (APS-C) film format was used in many cameras and produced negative film frames of 25.1mm x 16.7mm (aspect ratio 3:2). DSLR cameras rely on expensive-to-produce technology. Cropped sensors are cheaper and easier to make than full frame. They are lighter and smaller too. The DSLR market is reliant on the ASP-C sized sensor range for consumer and budget priced cameras. The cropped format is also used in some of the pro-models.
The classic sized APS-C format for film was a specific size. The APS-C digital sensor has a range of variants around sensor model, manufacturer, camera and other factors (eg. mirrorless etc). Typically, crop sensor sizes range from 20.7 × 13.8 mm to 28.7 × 19.1 mm. These may be superseded by new models. The cropped sensor format may vary between camera makers. Generally the lens designation will identify if the lensis suitable for a camera, manufacturer and lens mount. However, some lenses can be used on cameras which are either cropped or full frame. Some lenses can be used on both sensor types. The lens designation will normally make those distinctions clear.
Smaller sensors allow cheaper lenses. The image circle they project onto the cropped sensor is smaller than for a full frame. This makes it possible to have smaller, more compact lenses. However, it prevents lenses designed for APS-C format being used on full frame cameras – the image circle is too small. Full-frame lenses normally work on an APS-C format camera, it does not work the other way around.
Lens designations – frame size
Each manufacturer has a specific marque used to designate the lens-match to sensor format as identified below…
|Manufacturer|| Full frame
3rd party mounts
Other related sources…
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