What is a full-frame SLR camera?

Full digital SLR means that the size of the photosensitive element of the digital SLR is the same as the size of 35mm photographic film (that is, full film), which is about 36×24 mm. The most common all-in-one cameras on the market are top-end and high-end models from various manufacturers. There are no entry-level all-in-one cameras, and none priced below 10,000. Canon 1Ds Mk3, 5D mk2, Nikon D3x/D3s, D700, and Sony a900 are all all-in-one models. , generally all have obvious marks on the fuselage, each brand is different.

The sensor size of the APS-C format is 23.6x15.7mm (Nikon, Sony and Pentax) or 22.2x14.8mm (Canon). Because the photosensitive element is the core of a digital camera, larger photosensitive elements are more expensive and more difficult to manufacture, so there are digital cameras with photosensitive elements smaller than the size of 35mm film (in fact, early digital cameras including digital SLRs are Not all of them, because it was technically impossible at the time). Entry-level and mid-range models are all APS-C format, such as the popular Canon 550D, Nikon D90, and D80. In addition, Sony's mirrorless NEX-3/5 and Samsung single-camera NX10 and NX100 are also APS-C format. .

In addition, there is also APS-H format, only Canon 1D series, the size is 28.7x19. Sigma's Foveon is about 20.7x12.8, Panasonic and Olympus' M4/3 systems are 17.3x13mm, and consumer cameras have 1/1.7-inch, 1/1.8, 1/2.5, etc. sensor elements. It's so pitiful.

Because the higher the pixel density, the greater the impact on image quality. Therefore, under the same number of pixels, the larger the photosensitive element, the lower the pixel density, the better the image quality. In addition, the larger the photosensitive element. , the shallower the depth of field, the easier it is to obtain a background blur effect, and a wide-angle lens can also obtain a larger viewing angle.

The same lens requires different conversion coefficients on different sizes of photosensitive elements. The 1D series is 1.2, Canon's APS-C is 1.6, other manufacturers basically use 1.5, and M4/3 is 2.0. In other words, the 18-200 lens with the same focal length is equivalent to 27-300 on the D80 and 28-320 on the Canon 50D. The full lens can be used on both full body and APS-C bodies, but the "digital "Special lenses" (that is, special lenses for APS-C format) can only be used on APS-C cameras. There will be black borders around the photos when used on full-frame cameras. Regardless of whether they are full-frame lenses or not, they must be used on non-full-frame cameras. Multiply the conversion factor. Because the focal length has changed, the angle of view and composition of the same lens on different bodies may be different, and the purpose may change.