To eng01170, yes, you really asked the questions.
For MTF measurement, one need work out the knife-edge spread function (distribution) and then calculate.
To have a benchmark which could be applied to all lenses is impossible. For example, for a zoom lens, wide angle side may suffer from more distortion, light falloff and lateral color, also the MTF drops a lot at the edge; at tele side, however, the MTF may be lower but be more uniform for the whole aperture, also lateral color may be obverious; at normal side (middle focal length), lens may have most of aberration balanced and perform better.
Different company has different design requirement, like Nikon and Canon, they may concern lens performance more on the centre than on edge, but for Pentax, I saw some lens have quite uniform distribution of MTF. So, when conduct testing, I have to bear all these factors in mind so that the test result come out is complete.
Any way, all the values I test is quantitative, based on which I will do some comparison and advise.
To king kong,
Fine. Thanks.
Basically, I can test all the lens you mentioned and pointand shoot camera as well. However, manual focus lens may not be accurate, I suppose.
I am testing the optical performance of the lens. I can test focal length, field of view, MTF, light falloff, lateral color and distortion. I am not going to test something like, the AF speed and noise of motor etc.
Hope more people show they interest and let me know by reply my post.:thumbsup: