DSLR vs CSC: 02 Viewfinder
DSLRs have an optical viewfinder which shows the scene as it is seen through the lens.
Compact system cameras can’t have an optical through-the-lens (TTL) viewfinder because they don’t have a mirror to reflect light into the pentaprism/mirror.
In many cases the image is composed on the screen of a CSC, just as it is with many compact cameras.
However, in some cases there is an electronic viewfinder (EVF), which is made from a small screen (often an LCD).
Some cameras are even compatible with an optional external EVF.
These allow the image to be composed with the camera held to the eye, which is useful in very bright conditions or with moving subjects.
Crucially, an EVF shows the image that is formed on the imaging sensor. The first EVFs were low-quality affairs and this has given them a bad name that has been hard to shake-off.
The image in the EVFs in most modern compact system cameras may not be quite as smooth as the one in an SLR’s viewfinder, but it has the advantage of being able to show how the image will look when it is captured, taking into account the exposure, colour and white balance settings.
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