Aperture Guide

A quick guide to apertures available on the Nikon D90, in 1/3 stop and 1/2 stop increments:

f/0.95 f/1.0 f/1.1 f/1.1 f/1.2 f/1.4 f/1.6 f/1.6 f/1.8 f/2.0 f/2.3 f/2.3 f/2.5 f/2.8 f/3.2 f3.3 f/3.5 f/4.0 f/4.5 f/4.8 f/5 f/5.6 f/6.3 f/6.7 f/7.1 f/8.0 f/9 f/9.5 f/10 f/11 f/13 f/13 f/14 f/16 f/18 f/19 f/20 f/22 f/25 f/28 f/29 f/32 f/36 f/39 f/42 f/44 f/52 f/58 f/61 f/64

These values, for the most part, have been taken directly from the camera. Some of the 1/2 stop values, when rounded by the camera, are the same as the 1/3 stop values. Using this chart, we can see for example, that an f/1.2 lens is a full stop faster than an f/1.8 lens, but an f/1.8 lens is only 1/3 stop faster than f/2.0. However an f/1.8 lens is a significant 1-1/3 stops faster than an f/2.8 lens, a common aperture value. The holy grail of speed, the f/0.95 lens, is just slightly over a full stop faster than an f/1.4. Using Nikon’s claim of a 4-stop advantage using VR, the 16-85mm f/3.5-5.6 would behave similarly to an f/0.95-2.0 lens in cases where it was not used to stop action. In reality however, it would be closer to f/1.2, a three-stop advantage. Not too shabby. On the other hand, the 70-300mm f/4.5-5.6 would be the equivalent of f/1.6-2.0. Still not shabby. So, unless you are shooting sports or other action, purchasing a fast f/2.8 telephoto may not be entirely necessary. It will however cut down significantly on flash recycle times, which may be a consideration.