Leica Elmarit-R 28 mm f/ 2.8 Lens Manual
Chapter 1
Leica R-Lenses
1
From 1925 to 1950, the lens with a focal length of 50mm was
the most used standard lens. Much has been written about the
diagonal of the film format being the dsetermining value for its
definition as the ‘standard lens’. The length of the diagonal of
the 35mm-format is 43mm (to be precise: 43.27mm) and there-
fore this should actually be its focal length. In fact any focal
length from 43 to 58mm has been used for the standard lens.
More importnat from my point of view are the perspective and
angle of view that one gets with a 50mm lens. When Prof. Berek
was calculating the first 50mm lens for the new Leica format as
it was known in those days, he was without doubt searching for
a balanced compromise between useability, speed, depth-of-
field, and optical performance. In addition, the lens should
exploit all capabilities of the somewhat unorthodox image size
that Barnack had chosen. The aspect ratio of 2:3 (1: 1.5) was
known from the then ubiquitous 6x9cm print size, but most
paper sizes had an aspect ratio between 1:1.25 und 1:1.38. The
"golden section”, i.e. the ideal proportion as used by painters,
had an aspect ratio of 1:1.62, slightly more than Barnack’s for-
mat.
__Artistic considerations
The Leica was intentionally designed as a camera to be used in
an upright posiion and in front of the eye. The maximum vie-
wing angle of humans is limited to 140 degrees in the vertical
direction and 200 degrees in the horizontal position. And this
ratio (1:1.43) is quite close to the ratio of the Barnack negative
size. What you can intuitively observe with your eyes, can be
captured almost identically on the negative. A small trick: when
you observe the scene with squinted eyes you will see a blurred
picture, but the outlines of subjects and their distribution over
the image area can be detected with ease. This helps to find a
good or interesting composition. The viewing angle of 47
degrees and the perspective (meaning the relationship between
the size of the depicted objects at the different distances) of
the 50mm lens supports the correct reproduction of the intuiti-
ve observations on the final print. The first generation of Leica
photographers almost exclusively employed the 50mm lens,
evan after the introduction of interchangeable lenses. And with
this lens, often stopped down to 1:8, photographic masterpie-
ces have been created. A picture originates between the ears,
but one needs an instrument that can capture the scene on film
exactly as it was experienced. The ‘50mm’ has much more
potential than is often believed.
In recent times it has gotten a bit quiet around the normal lens.
You will quite often hear that the focal length 35mm represents
the natural perspective in a more pleasing way. In part this is
just a matter of taste or opinion. Every picture has a main moti-
ve and some environment surrounding the subject. Or in other
words: a foreground and a background. In photographic compo-
sition the size relation between main subject and background is
quite important. If you look closely at pictures, you will often
find that the picture taken with a 35mm lens is a bit tense and
intrusive, because of the prominent position of the main sub-
ject in the focus of attention.
The ‘50mm’ is a bit more balanced in its representaion of bak-
kground and foreground and the size relations are often harmo-
niously proportioned. Both perspectives are valid and one
needs to understand the subtle visual differences, as this helps
you to make the right decision for the selection of a lens.
__Optical considerations
The optical evolution normally proceeds in a smooth and order-
ly way, but sometimes we note an unexpected jump. The first
theories about aberrations were developed by mathematicians
and practical experience was gathered by makers of telescopes
and microscopes. It is therefore logical that maximum resolu-
tion is a very important quality criterion. You will not be happy
when the distinct spot in the sky is not a star but a double star!
The optical designers tried to correct the aberrations in such a
way that the resulting image point (the spot) was as small as
possible. Often this meant that the small spot was surrounded
by a larger area of halo or flare that reduced contrast. In those
days that was the least of problems. Already in 1936, Dr. Fricke,
Leitz Wetzlar, argued that edge sharpness was more important
than resolution. MTF measurements were not yet invented, but
his discourse pointed in that direction. In the fifties, TV became
a commodity. There was considerable research to match the
quality of the TV image to that of the 8mm movie format. The
TV image however is restricted to 625 lines in the vertical
direction and more resolution cannot be realized than is possi-
ble with these TV screen limitations.(this is identical to the cur-
rent dicussion about pixel size and number in comparison to
film emulsions. History repeats itself!).
Dr. Schade was the first person who discovered that an impro-
vement in contrast was the cause of a visually enhanced sharp-
ness impression, even with identical or lower resolution. This
knowledge, first employed in the TV design in America, has
been adopted by Dr. Mandler, Leitz-Midland, when he designed
the first Summicron-R 50mm f/2, introduced in 1964 together
with the new Leicaflex. This lens had a very high contrast and
image quality judged by the then accepted standards. The high
level of contrast was coupled in a smart way to a high level of
resolution and for a long period, because of its excellence in
terms of the micro-contrast at the limit of useable resolution,
this lens served as the reference lens for tests of film emul-
sions. If you are engaged in collecting Leica lenses, this one
should be in your collection as a significant milestone in lens
design. Since then, Leica designers have always been engaged
in optimizing, which is not the same as maximizing, contrast
and resolution at full aperture.