Focal length comparisons

Photographers considering a new lens purchase often have a hard time visualizing what differences the various focal lengths produce. Below are shown five different focal lengths and an example of their coverage. Anyone considering lens selection should also look at the brief essay calledAbout Focal Lengths, which describes how to use F stop ratios to select lens focal length spacing.

The photographs below show the Toronto skyline on a clear but somewhat smoggy day. This is noticeable in the slight haze visible in the longer focal length shots.

The camera used was aRollei 6008i. The lenses used were 40mm, 90mm, 180mm and 300mm in focal length. The last frame was with the 300mm and a 2X extender, for an effective focal length of 600mm. In 6X6cm medium format this is an almost ideal spacing of focal lengths, logarithmically placed about 2 "stops" apart.

I also show the equivalent focal length in 35mm terms. This is shown in yellow . The factor used is X.6.

40mm ( 24mm )

90mm ( 54mm )

180mm ( 108mm )

300mm ( 180mm )

600mm ( 360mm )