What is a varifocal lens?
A varifocal lens is one where the focal length of the lens can be varied. This is a fancy way of saying it is a zoom lens. Most varifocal lenses have, and in almost all circumstances should have, an auto iris feature, which is responsible for automatically adjusting due to different lighting situations.
A – A lens with an adjustable focal length. Varifocal lenses require focusing adjustments whenever the focal length is changed. They are described by magnification power according to the difference between the longest and shortest focal lengths. A 5mm to 50mm zoom lens has a magnification power of 10X. Also, a 10mm zoom lens has a magnification power of 10X. Many different varieties of varifocal lenses are available including both manual and motorized versions.
