Lens review

Nikon Nikkor AF-S DX 18-70 mm f/3.5-4.5 IF-ED

8. Vignetting

The situation is worse in wide angle mode, with a wide open aperture, when relative light fall off in the corners reaches as much as 50% (twice the diaphragm value). Stopping down the lens helps, but just slightly. For f/4.0, vignetting reaches 42%, for f/5.6 it drops to 28%, and for f/8 to 20%. Even stopping down the lens to f/11 does not make the vignetting level satisfactory, which would be 10% or less.

In the middle of the focal length range the situation is fortunately better. For 30 mm and a diaphragm of f/4.0 the light fall off in the corners of the frame is 23% (0.75 the value of the diaphragm). For f/5.6 it drops to 13%, and f/8 it decreases to a satisfactory level of 10% and less. For a 50 mm focal length and a wide open aperture the vignetting value is 24%, for f/5.6 it is 17%, and for f/8 it is only 9%.