Quote Originally Posted by Les Sarile View Post
BTW, I owned a few Canon L lenses and those were some of the best lenses I ever used and I was therefore apprehensive using old - secondhand, manual focus lenses. However, after qualifying some of my acquisitions with Kodak Techpan processed in Technidol and evaluated under great optical magnification, I know that the primes I have tested will not be outresolved by any DSLR today.
I think for black and white work on film your assessment may be completely valid, but for colour work on either digital or film, there are some caveats. Testing with B&W film as you did may obscure many colour-coupled lens flaws such as chromatic aberrations and purple fringing. For this reason, one should test every lens in the intended end use. A good example of a great lens on film, but very mediocre on digital, is the Nikkor 400 f/3.5 IFED. There are many other examples, too. And although it is maybe not what you meant to say, I doubt that resolution is the only or even most important characteristic of an optic. I do agree that Canon L lenses are mostly great, and so are the APO and ED counterparts from Minolta, Nikon, Leica, Olympus etc. But there are many lenses that are equally great that are not necessarily L or ED. Some are downright unassuming, like the Nikon Series E 75-150. You are correct in saying that old manual focus lenses can be surprisingly good, but I would add a few zooms to the list of primes.