Brian Sweeney , Feb 24, 2004; 06:31 a.m.
I have used the Nikkor 55mm F1.2 lens for quite a long time and have never had a complaint. Reading "net reviews", this lens is described as a "Dog". I went back and read the May 1976 Popular Photo reviews of the lens and was surprised to learn that:
1) It is a true F1.20 and a T1.25
2) Over the central 2/3 of the image it was slightly sharper than the 50mm F1.4 out to F5.6. At F5.6 the F1.4 lens had a slight edge.
3) Coma was no worse than the hailed 50mm F2.
4) As it is a multicoated 7/5 formula it is probably the fastest T-Stop Nikon lens made for consumer cameras. The 50mm f1.2 and 58mm F1.2 are 7/6 formulas, so two extra air/glass surfaces. I am not sure if the 9element 50mm F1.1 RF lens can beat a T1.25.
The Olympus F1.2 did slightly better, but it was a F1.31 measured and T1.42.
The Leica F1.2 aspherical has the sharpest center, the worst 1/3 out, the best 2/3 out and the worst edge. It was F1.20 but slower at T1.30.
Reading a later October 1976 announcement of the 58mm F1.2 Noct-Nikkor, it was clear that this lens was made for low-light only work. The lens was optimized for best performance at 5~10LP/mm. That is a far cry less than the 50LP/mm that the 55mm F1.2 was blasting away wide-open.
I do not know if this is a case of users comparing lenses that have taken a beatingand getting misaligned optics over the years OR a case of if it's that fast it can't be any good unless its aspherical.