The Online Photographer has posted some pointers on how to determine a good performance from a zoom lens by stressing it, i.e., using the lens in such a way that its weaknesses are exposed.
By pushing it to its limits, you’ll find out how good (or bad) your lens is. Mike Johnston suggests putting it through a few paces such as the flare test for ghosting and veiling glare.
Other tests include shooting with the lens outside its aperture sweet spot, and testing for its field curvature, focus distance, bokeh and a few other things.
Mike’s thoughtful article actually starts with a few good tips on how not to stress a lens, showing us how to see the best performance of our lenses under optimum conditions.
[Via: The Online Photographer]