P3D Modern v Classic Lens Contrast

[Eric Goldstein <egoldste@xxxxxx>]

I our discussion of modern lens performances versus the triplets and
tessar-types from the 50s, bobh wrote:

> even
> multi-coating doesn't do much for these lenses over regular coating

This is actually an interesting case study... in the late 60s ('68 I
think) a Pentax/Zeiss collaboration produced the first modern
multicoatings for lenses. The efficiency of these coatings was so much
greater and the contrast they produced so much higher (not necessarily
"better") that Nikon bit the bullit and paid the substantial licensing
fee for this technology, gambling that it would be worth the cost for
the reputation they could gain in the emerging market of
consumer/prosumer/professional SLR 35mm cameras. Zeiss of course was
pulling out of this market and started making lenses for pro cameras
such as Hasselblad, and Pentax, though they did not have the financing
or accumin to gain an aggressive foothold, none-the-less did gain a
reputation for optical excellence which survives to this day... Canon
OTOH gambled the other side and did not license this technology and went
with their own Super Spectra Coating, a single coating process. History
shows the result: a lesser reputation and market share at least into the
early 80s.

This may seem oversimplified and clearly there were other factors at
work but many business and photographic historians would point to this
single instance of adopting or not adopting a single technological
advance as pivotal in the business life cycle of these companies, at
least till the patent on multicoating expired!

This then lead to the contrast craze and the resulting practice of
manufacturers apotizing their lenses for contrast instead of resolution
which followed in the early '70s....

> the so called design for
> contast that chooses the large core Airy disc center with less flare
> over the smallest which evidences flare rings (but gives highest
> resolution) makes prints and slides look snappy but they may fall
> apart on large blowups. Zeiss decided in one paper about thirty
> years ago that designing to give over 40 lp/mm (in a 35mm frame) was
> a waste of time as few pictures were enlarged and this allowed one to
> optimize Contrast which looked sharp.

Leitz, too... I have a Noctilux piece which discusses this tradeoff in
detail. Yes, the classic lenses often have higher resolution and may
well hold up better under high orders of enlargement. Stereo shooters
usually deal with hand viewer magnification of 5x or the projection
equivilant, and so resolution beyond this limit is typically not an
issue, but of course apparent sharpness or edge contrast is...

Bob also mentions that coatings don't have nearly the benefits with
simple prime lenses that they do with complex zooms. While this is
clearly true, even triplets/tessars have 6 air-to-glass surfaces and the
benefits of the improved coating technology of '50s versus today are
visible... with efficiency gains easily on the order of 5% or more per
surface producing over a half stop improvement in transmission with even
simple lenses and commensurately less internal reflection.

Don't get me wrong... I love the classic lenses and use a '53 Summicron
(extremely high resolution), '55 Planar, Realist Ilexes ('47)  and
Ektars (early 50s), '55 Tessars (Belplasca) and others regularly in
addition to more modern Canon, Zeiss, Cooke, Fujinon, etc in my work and
my leasure. From experience I feel the classic lenses are different from
the modern ones, and the artistic photographer needs to know and master
these differences to make the best use of them...

Now if you REALLY want to open a can of worms, should we talk about
"roundness," "plasticity" or "character" of the classic versus modern
lenses (criticized for being "sterile," "non-dimensional" and "flat")?
Or the appearance of the out-of-focus areas (German glass supposedly
superior to Japanese)? Or should we just keep quiet and go out and
shoot? 8-)


Eric G.


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