Let me add that someone should post this to the LUG list--that esteemed body
could use this piece of research!
Alex
;o)
In a message dated 2000-01-29 11:31:33 AM Eastern Standard Time,
image66@xxxxxxx writes:
<< Questions come up periodically regarding why pros still use Lieca
rangefinder cameras. The origional reason has almost been forgotten--Lens
Element Wear.
Years ago when SLR cameras started to make a major headway into usage with
the Nikon F bearing down on the photojournalism world it was quite apparant
that the Lieca lenses remained sharper than the Nikon's. Opinions were
formed by wannabe technoids, but conclusive research was done at the
Fareway Lie Archival Research Enterprise (FLARE) and Golf Course.
This research resulted in a startling discovery. Photons flowing through a
glass surface causes a molecular transfer throughout the lens element which
can alter the overal shape and optical characteristics of that element. As
a lens ages, its optical formulation can actually change resulting in less
resolving power. Furthermore coatings can change and multicoated lenses
will slowly fade into single-coated lenses. All lenses were multicoated,
but most of the older ones just have the yellow coating left.
With rangefinder cameras such as the Lieca, photon flow is limited to only
the times of the exposure, wheras an SLR will allow photon flow anytime the
lenscap is off. What is surprising is that 40 year old Leitz lenses
exhibit less lens element wear than most SLR lenses subjected to just a
couple hours of use. Since the Lieca rangefinder lenses don't wear out at
nearly the same pace as SLR lenses they remain sharper longer. Lieca
provided test lenses which were sealed against light contamination to the
various photography magazines which is why Lieca lenses always tested as
among the sharpest in existance.
Additional research revealed the cause of flare. Lens elements can pass on
only so many photons. Excessive photons are stored in the lens element
like static on a boy shuffling across a cheap carpet. These stored photons
manafest themselves as "flare". Older lenses (mistakenly called single
coated lenses) have more photons stored up which makes them more suseptable
to flare. Newer lens designs contain elements labeled ED, Rare-Earth, ELD,
etc. which do not store photons. These elements are also less suseptable to
formulation alteration from usage too, but can suffer from
DeUglyFaceCrackDeLens Syndrome. It is important not to use these modern
lenses around truely scary looking people.
The rate of wear is expressed with the following formula: YA=R(i)/GH-t
The photon buildup is expressed as: Ge=Tr-E/a+L
To discharge the excessive photons from your older lenses the repair
procedure requires you to place the lenses on their sides with the lens
caps off. A blacklight is placed in front of the lenses and an infrared
lamp placed behind. This must be done in total darkness, so it is best to
use your darkroom for this procedure.
Returning your lenses to multicoat status is not possible, but the effects
of coat reduction can be helped by this procedure. As always YMMV.
Ken Norton
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