Quote Originally Posted by LJSLATER View Post
Ian, your post makes the most sense to me. I have no expertise in the field of optics, but it seems to me that coatings become more and more important as the number of elements and glass-to-air surfaces increases.

My old 135/3.5 (four elements, three groups) has single coatings and my slightly more modern 18/4 (13 elements, nine groups) has more advanced multi-coatings, but the earlier, simpler telephoto definitely packs more of a visual punch.

I agree. Many single and uncoated lenses were designed to be sharp and flare resistant. By using low number of elements and cemented groups, reflections were minimized.

In addition, there are many more things that go into a high quality lens. This is rarely discussed. Proper glass composition, polishing, alignment, and spacing make a huge difference. For instance, in the Zeiss tessars, the cemented surfaces are curved. This adds to the expense. I've heard that some other manufacturers use a flat surface in order to cut costs. I don't have any examples offhand sorry.

When you consider many modern lenses have ten or more elements, coatings and construction must all be done extremely well ..