The Sigma EX DC 30mm F1.4 for Sony is a fast prime lens with a focal length of 30mm, designed for use on Sony cameras with an APS-C sensor. It has a maximum aperture of F1.4, which allows for a … Read the rest
Divide the two different ‘mm’ numbers given on the lens.
For example if you have a lens with 21 – 1365 mm
21 – 1365 mm = 1365 mm divided by 21mm = 65 x zoom
Or the Canon … Read the rest