To measure and compare the resolving power of each lens using the Nikon D80, we photographed the Enhanced Digital Camera Resolution Chart with each lens set to a focal length of 35mm and an aperture of f8. The D80 was set to Aperture Priority, Large Fine JPEG mode and its Optimise Image parameter set to Normal. All four lenses were tested within moments of each other under identical lighting conditions.

The crops are taken from the original images, saved as High Quality JPEGs in Photoshop CS2 and presented here at 100%. Each number represents 100 lines per picture height (lpph), so a figure of 20 means a resolution of 2000 lpph.

In terms of horizontal resolution, the DX 18-70mm edged ahead of the pack to deliver the best result here of 2200 lpph, although the budget DX 18-55mm was impressively only a fraction behind with 2175 lpph. The DX 18-135mm and DX 18-200mm followed with 2150 lpph each.

Moving onto vertical resolution, the DX 18-70mm once again came top of the group with 2200 lpph, with the DX 18-55mm falling to match the DX 18-135mm and DX 18-200mm with 2150 lpph.

While there are measurable differences between these lenses and a leading result for the DX 18-70mm, the relative closeness between their scores means it's fair to say none of these lenses seriously compromise the D80's resolving power. Also note the higher contrast result from the DX 18-55mm under identical lighting conditions. Finally note when equipped with a 50mm f1.8 lens set to f4, the D80's horizontal resolving power can be increased by a fraction to 2225 lpph - see our 10 Megapixel DSLR group test.