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An imaging sensor with the same size as film used for the respective format of camera. See also Crop factor and APS-C.
Describes how much an imaging sensor has been cropped in relation to its full-frame equivalent. It always describes how many times larger the full-frame is in relation to the cropped sensor. Take an APS-C sensor with a crop factor of 1.6, for instance. This indicates the sensor is 60% of the size of a frame of 35mm film. The crop factor is used to calculate how much of the equivalent of the full-frame field of view the cropped sensor will have with a lens. In order to calculate this, one multiplies the focal length of the lens by the crop factor. A 1.6 crop-factor, for instance, will give a 100mm lens the same field of view as a 160mm lens on a full-frame camera.
Advanced Photo System type-C should not be confused with the Advanced Photographic System (APS) camera/film system, since the former is digital and the latter is analogue. APS-C is a type of image sensor found in certain digital single lens reflex (DSLR) cameras. These sensors are smaller than the ones used for the conventional 36 mm x 24 mm (35 mm) sensor SLR cameras (also called full frame DSLR cameras). Being smaller causes a 1.x multiplier for the effect of the focal distance of the lenses, in comparison with the effect of those lenses on conventional 35 mm film SLR cameras or full frame digital SLR cameras. Several manufacturers produce cameras with an APS-C sensor and some even make lenses especially for them. These lenses are found in the Canon EF-S, Nikon DX, Pentax DA and Sigma DC ranges, to name the most popular ones. The most common multiplier ratios are 1.6 (Canon), 1.5 (Nikon, Fuji, Sony, etc.), 1.3 (Canon). (1.3 crop sensors are also sometimes called APS-H.) Most manufacturers not only produce cameras with these cropped sensors, but also offer DSLR cameras with full frame sensors.
Extreme wide-angle lens that gives 180 degrees coverage and is uncorrected for curvilinear distortion so you produce a heavily distorted photograph. If the photo turns out to be rectangular or circular, and how distorted it looks, depends on the lens and the camera. There are basically two kinds of fish-eye lenses for photography: 1. Lenses that produce a circular image, typically 8 or 10mm lenses, used on 35mm cameras or full-frame digital cameras. They produce a circular image with dark corners (due to most photos being rectangular). A similar lens is available for digital cameras with a so-called "cropped sensor". To achieve the same circular effect, it's a 4.5mm lens. 2. Lenses that produce a rectangular image. These lenses enlarge the image to cover the whole rectangular frame of a photograph. They are typically 15 or 16mm lenses. On a 35mm or digital full-frame camera they produce rectangular but still heavily distorted images without dark corners. The same lenses on a digital camera with a cropped sensor will still have a distorting effect, but less so. Fish-eye lenses used to be prime lenses only, but one company has gone so far as to produce a 10-17mm fish-eye zoom lens. This lens still produces distorted, curvy images, but zooming in lessens the distortion.
The action of adjusting the lens so that the subject appears sharp on the film or CCD. Most cameras now have automatic focus (AF), some have manual focus override (MF) and some have a fixed focus (F) lens that ensures things from about 1.5 meters to infinity are relatively sharp. A few cameras have a power focus (PF), which is a manual method but using a motorised focusing ring. Buying advice: Autofocus is essential if you want to use the camera effortlessly, but occasionally the system is fooled, so make sure the camera has a focus lock or infinity setting or, better still, full manual control. Also check what the closest range is. Some only go down to about one meter which is useless if you want to fill the frame with a small object such as a flower or piece of jewellery.
A specialist camera designed that produces an elongated image by exposing using more than one film frame. A 35mm version will use one and a half frames to create a 24x54mm image and a 120 film type can capture 6x17cm images. When printed these images look stunning especially landscapes which is the main use for this type of camera. There are other panoramic models made that revolve to record a full 360 view. This can be joined and viewed digitally so you look as though you are in the centre and as you scroll with the mouse you turn around inside the view.