Originally posted by civiletti Theoretically this may be true, but calculating comparative factors for several lenses tested on various cameras has shown me that results are fairly consistent, enough so that I would put more weight on such MTF comparisons than I would on reduced size JPGs posted on the internet or someone's opinion based on non-technically judged results.
personally, it is still tricky to make lens comparisons done on different systems. PZ for instance wouldn't had done a retest of the old tests conducted on the Pentax lenses on the camera that they used if there is the body has no significant influence on the MTF figures. there is an obvious difference in the numbers between the Pentax cameras used, so we can also think the same with other system. to be more precise, it is better if both lenses are conducted with the same camera. and I don't think we have that data. although from real world use, we can still see the difference (as long as it is not altered). otherwise, what is the point of doing side by side image comparisons. it is not necessarily quantitative measurement, but does support whatever MTF value there is. aside from that, MTF figures are also prone to errors due to other factors involved such a a poor sample.