Quote Originally Posted by Richard Jepsen View Post
Last year I bought used metal El-Nikkor F/4 lenses to replace community DR crap 3 element and some F/3.5 optics. I found the F/4 had better contrast than older (somewhat dirty) Leitz F/4.5 optics. In my judgement (no testing data) the Nikkor F/4 performs as well at F/8 as the faster El Nikkor. If enlarging past 8X all bets are off since the F/2.8 is multicoated and 6 elements. The F/2.8 should be better to the corners on a wider range of apertures. The bottom line is the El Nikkor (Tesser) F/4 is a very good lens if used in it's sweet spot.
I used the ,almost universally derided ,F/4 Nikkor 50 for years,before I traded up to the 50/2.8,then the 63/2.8.
I have grain-sharp,corner to corner enlargements from all of these lenses.Rumor has it the 63/3.5 was the pick of the litter.
It is a tradeoff between sample variation,and alignment IMHO.And the 2.8F lenses are all great at 4-5.6,and increasingly poor at F8 & below.