Today most camera’s have the capacity to focus, that is previously there were cameras that had an infinite preset focus but today any camera selling above 50- 60$ have an auto focus system. Auto focus is a system where the focusing lens arrangement is repositioned to attain a focus image, by the camera itself to get a sharp image.�
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Auto Focus Sytem
The above image shows the standard auto focusing system in a very simplified diagram. This is the system that most DSLRs implement. Such a system is expensive dues to …

SLR cameras show the image that is actually going to come on the sensor in the viewfinder. They do this by using a mirror in front of the sensor and the reflecting it to the viewfinder. The problem comes in the second reflection that is we need to get a 90 degree turn to get the image on the viewfinder here comes the pentaprism or the pentamirror
Lets see the principle behind this first, it will be easier to explain this using a pentaprism so we are going to talk in …