Leica APO-TELYT-R Camera Lens User Manual


 
Chapter 3
Leica R-Lenses
9
You will have to find subjects that have extremely fine details to
start with, and then you must take pictures at quite a large
distance, because you need a high value of negative magnifica-
tion, and then you must enlarge the tiny negative to big propor-
tions. This places the imaging chain under heavy strain.
For example: I use a subject that consists of a black-and-white
line pattern with line widths of 0.25 mm. The pattern has a
resolution of 2 Lp/mm. I need a negative magnification of 100x
to get a resolution of 200x on the negative. Using my 280 mm
lens, the distance to the subject will be 28 meters (92 feet).
But that positions me so far away from the subject that I cannot
even see the pattern! To achieve an accurate focus I affixed the
pattern to a large piece of white cardboard with a big black line
on it for easy focusing. It is too optimistic to assume that all
my problems have now been solved.
The focusing on the viewfinder screen is performed visually,
with the eye being the final judge, but the eye is easily fooled!
Therefore you have to bracket your focus by making several
exposures with a slightly shifted focus in both directions from
the original focus. The amount of that shift is a matter of expe-
rience: I would suggest that you begin with one or two millime-
ters at a time. The accuracy of Leica R8 or R9 cameras can be
taken for granted! If errors occur, they will be human errors.
Cable release, mirror lock-up and fast shutter speeds are fun-
damental requirements. A shutter speed of 1/30 second, even
on a heavy tripod, is not the best solution, it may even be hope-
less.
The lens mount of the 280 mm lens has a built-in tripod socket,
which is a necessity. But camera- and lens-induced vibration
frequencies cannot be avoided (this involves thousandths of a
millimeter). Experienced wildlife photographers use everything
from sandbags to bricks attached to the tripod in order to redu-
ce vibrations. I used weights placed on the body and on the
front part of the lens in order to eliminate the tremors.
This may sound very elaborate. It may be partly so, but with
some experience it becomes a natural habit in high-resolution
photography. Without specific experiments, you will never
master the imaging chain. I wish to dispel the impression that
this type of photography is as easy as shooting from the hip.
But it is not a big problem either. Leica camera bodies and len-
ses are not the weakest links in the chain. And it is very gratify-
ing to discover details in projected images or in big prints that
you never knew were there in the first place!
You will get the best performance of around 150 Lp/mm with
Agfa Copex exposed at a film speed of ISO 12 to 16 and proces-
sed in Spur Nanospeed developer, or Kodak Technical Pan
exposed at a film speed of ISO 20 to 25 and processed in Spur
Dokuspeed developer. There are no secret tricks here: just
develop according to normal practice. With Agfa Rodinal devel-
oper you will have to experiment: at a dilution of 1:50, you will
get quite a steep gradation. And users have reported very good
results at dilutions of 1:100 and even 1:300 (this maybe a
secret tip!).
Up to 110/120 Lp/mm can be achieved with ISO 100 slide
films from Fuji (Velvia, Velvia 100F, Astia 100F) and Kodak
(E100G/GX). The advantage here is the higher film speed.
Current ISO 100 black-and-white films can deliver up to 100
Lp/mm and slightly more with dedicated developers and speed
settings (often ISO 64 and 50). Recommendations are not easy,
because every worker has his or her own methods and devel-
oper solutions. You need a developer that has a low amount of
sulfite. The formulas from noted experts like Beutler, Windisch,
Cyril Blood or Crawley (FXl) are good starting points.
LEICA APO-TELYT-R 280 mm f/4
Picture: Martin Trippen