How to make Dioptric Correction in camera
Dioptric correction on a camera is the correction of the viewfinder focusing. In simpler words, it is matching the power of your glasses (if you have one) with the viewfinder.
Camera filters and their effective use
In old times of film cameras, use of filters during photography was a common thing. A wide range of filters were used to achieve different effects. Amber, yellow, red were some of the common colour filters. These filters were used to suppress certain wavelengths thereby accentuating the effect of the others.