dante stella stories photographs technical guestbook

Pete and Repete were walking along. Repete tripped and fell.  Who is still standing?
 
Optical cloning?
 

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What is going on here?

The pictures above were taken with two different lenses, fifty years apart, with a pair of lenses that were made for different cameras, with different optical fomulas, different glass indices, and different element and group counts. The only common thread is that the two lenses have the same focal length, and both were shot wide-open at one meter.

Notice just how similar the rendition is of the flowers (granted, one has more center contrast, but we'll get to that in a minute), the stems, the lines around the walls and the telephone are with each other. In fact, you would very hard-pressed to tell the difference between the two shots. Such an extreme similarity almost begs the question of whether one lens, designed in 1999 with the aid of computers is designed to mimic a lens originally designed in 1927 and elaborated in 1953 with the help of an abacus.

— The picture on the top was taken with a 1953 50mm f/1.4 S.C. Nikkor, which is a close copy of a prewar Zeiss Sonnar, but with coatings and a slight recomputation. It has one single-lens element and two triple-cemented elements. It is asymmetrical.

— The picture on the bottom was taken with a 2000 50mm f/2 Konica M-Hexanon, which is a close copy of a Zeiss Planar lens. It has six elements in five groups, and it is symmetrical.

The contrast different you are seeing is largely attributable to the fact that the Nikon lens is not very contrasty wide-open. When you stop a Nikkor 1.4 down, it becomes a lot more contrasty, as much as the Hexanon — but contrast was not the focus of this exercise.

If there's a lesson to be learned here, it is that you shouldn't automatically assume that one formula of lens will produce a result that is any different from the next. Modern optical software can reproduce the aberrations of old optics in new ways.

DAST