A few of the more expensive DSLR cameras are described as ‘full frame’ as the size of sensor is the same as a frame from a 35mm film camera (the rest of the DSLR cameras on the market use smaller sensors). The use of a larger sensor has a few advantages and disadvantages for potential buyers of these cameras. As the sensor of a full-frame DSLR is larger it has the potential to offer higher quality images.
This is, however, dependent on the lens that is used in conjunction with this larger sensor. These full-frame DSLRs cannot use lenses designed for the DSLR cameras that use smaller sensors without issues or problems arising, e.g. the owner of a DSLR with a smaller sensor who wants to purchase a full-frame camera by the same manufacturer may not be able to use the lenses they already own on this model unless the lenses they have purchased were designed for full-frame sensors or 35mm film. Nikon owners may be able to place a Nikkor DX lens designed for a Nikon D300 on the full-frame Nikon D3 but will have to capture images at 5 megapixels instead of 12 megapixels. This is because lenses designed for reduced-frame sensors do not create an image big enough to cover the larger full-frame sensors.
The full-frame lenses are more expensive to build than lenses of similar quality designed for reduced-frame sensors. If a photographer aspires to owning a professional quality DSLR that uses a full-frame sensor they need to purchase wisely.
Size of the Sensor:
The size of the sensor has an impact on the magnifaction factor that a photographer will experience with the lenses they are using, e.g. a 200mm lens on a Nikon D300 magnifies the image 50% more than if the photographer uses the same lens on a full-frame Nikon D3 (a magnifaction factor of x1.5). Manufacturers often quote these magnifaction factors for assessing the equivalent focal length of lenses when used in conjunction with a camera with a reduced-frame sensor. Nikon DX is x1.5 while Olympus quote x2 for their cameras using the four-thirds system sensors. A wide – angle 24mm lens is a wide-angle 24mm lens on a camera with a full-frame sensor but becomes a not-so-wide 36mm when attached to a smaller DX sensor. This may have been a big selling point for a photographer who had not yet made the jump from film who owned a more traditional range of lenses but purchasing one of the popular ultra wide zooms designed for reduced-frame sensors gives back the angle of view that the photographer may have lost. The advantage for the owners of DSLRs with smaller sensors is that their telephoto lenses suddenly bring everything a lot closer than if they were using the same lens on a full-frame sensor.