On Classic vs Modern Glass:
The qualities most often cited when measuring the relative merits of a lens are sharpness and
contrast. There are other considerations, such as image circle, filter size, weight, etc, but the deal breakers
have always been sharpness and contrast. If a lens is unacceptably soft, it doesn't matter how small it is,
nobody's going to use it. Conversely, I have seen guys carrying comically large chunks of glass because they
think they've got a few lines/mm resolution over other lenses in the same focal length.
Why then would anybody well in control of their senses pay more, often far more, for lenses that are
not as sharp nor contrasty as their modern equivalents? This is something I wondered myself for quite a long while
until I finally got curious enough to buy one of these contradictions. It didn't take long before I knew exactly
what all the fuss was about.
Though there are scores of beautiful old lenses out there, amongst photographers there exists a few that have acquired
particularly strong reputations for their unique image qualities. Lenses such as Heliars, Dagors, Veritos, and Petzvals,
and all the variants thereof, are all highly esteemed. For a long time I had heard about the 'look' these lenses yielded,
always described with words such as smooth or creamy or pleasing. A photographer can only hear this
so many times before curiosity, or a craving for custard, gets the best of him, and he decides that it's high time to see
for himself what the real story is behind these lenses that are so highly sought after to sell for prices far beyond that
of, on paper at least, superior optics.
Rather than describe with words more fitting to a chocolate mouse then a lens, I will try to illustrate the
qualities of these lenses by showing identical images taken with 'classic glass' and their modern equivalents.
Every effort to minimize sources of variation was taken: exposure values were kept constant and images were taken indoors
under controlled lighting using a 'half-slide' technique - a method used to eliminate processing variables whereby
one 4x5 piece of film is used to record two distinct 2x5 images.
Curious what the Dagor Look is? How about the Heliar Effect? Emperor Hirohito was so fond of heliars that
he wouldn't allow his picture to be taken with any other type of lens. Sound strange? Read on...
---Classic Glass, Cont'd---