Archived posting to the Leica Users Group, 1996/03/08
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I dug through some of my archives last night to find out more about the lens
-- and here's the straight skinny:
The Biotessar formula is a six-element, three-group, design derived
from the basic Tessar formula: it has a doublet in front where the Tessar
has a singlet, and a triplet in the rear where the Tessar has a doublet.
The formula dates from the early 1920's and I could not find the name of the
designer. Surprisingly, Kingslake makes no reference to this design.
The standard Carl Zeiss Jena inter-War publication on their lenses,
_Zeiss Objectives: The Eagle Eye of Your Camera_, states that
[T]he Biotessar F/2.8 was constructed in response to
the repeated demands for a hand camera lens of very
great rapidity but of more universal application than
the f/2.7 Tessar. Compared with the latter the F/2.8
Biotessar marks a considerable advance in the field of
very rapid yet universal objectives, for even at full
aperture it gives excellent definition over the whole
field, whilst when stopped down to F/3.5 and F/4.5
respectively, it is not inferior to the Tessars of
these maximum apertures. The angle of firled for
which the F/2.8 Biotessar is recommended measures
fully 40 degrees.
The Biotessar was available in either 13.5cm or 16.5cm focal lengths
and could be had mounted in a Compur or Compound shutter, in the focusing A
mount, the standard N mount, or the recessed B mount. The diameter of the
outer lens ring was either 69mm or 70mm for the 16.5cm lens. The 1938 and
1939 Carl Zeiss Jena American price lists no longer list either focal length
with an inbuilt shutter, but do list them with the other three mounts. The
price of the 2.8/16.5 lens with the standard N mount was $154.00 in both
years. By way of comparison, the 3.5/16.5 Tessar cost $100.00 and the
4.5/16.5 Tessar $49.00. (This would be roughly 32 pounds sterling for the
Biotessar against 20 pounds for the f/3.5 Tessar and 10 pounds for the f/4.5
Tessar.) I do not have any Leica prices from this era at hand, but I
suspect other Stalwart and Intrepid LUG-Nuts will be able to provide
comparison data for Leitz for this period.
The lens in question is undoubtedly a large-format camera lens which
dates from either 1929 or 1930. It is probably in a standard N mounting.
The adaptor for bellows usage is an after-market conversion of some sort:
this kind of skilled machining was not uncommon in the inter-War era when
craftsmanship was the rule and thus could be had at a relatively low cost.
This is a fine lens of sound optical performance. Its manufacture
preceded the development (by Zeiss, of course!) of lens coating in 1936, so
this will produce a softer optical effect. It is both a curio of great
interest and a solid lens still capable of great usefulness some six decades
after its manufacture.
Marc
msmall@roanoke.infi.net FAX: +540/343-7315
Cha robh bas fir gun ghras fir!