I have received several requests by private message for specific information on
how to buy and use the Zeiss Jena lenses, and so I think I'll answer them all
at once here.
 
First, a very short history:
 
After World War II, the Zeiss lens factory in Jena found itself in the Russian
sector. (Germany was divided amongst the four victorious powers, with the
Russian sector becoming East Germany, and the French, British, and American
sectors merging into West Germany.) Many of the key scientists escaped, with
American help, into the western sector. They setup up a new factory in
Oberkochen, and that factory now produces Zeiss optics for high-end cameras,
among many other things. Some of the tooling and the designs went to the
Ukraine, and were used to develop a line of Soviet lenses following the classic
Zeiss designs. Those who remained continued to operate the Jena factory in East
Germany.
 
In the Communist world, Zeiss Jena optics were called "Carl Zeiss Jena" and used
their traditional lens designations, including Sonnar, Biometar and Flektogon.
In the west, it depended on the country. In the U.S., Zeiss Jena was not
allowed to call themselves "Zeiss", and the products exported to the U.S. were
labeled Jenoptik (in the case of binoculars) and "aus Jena" in the case of
camera lenses. Zeiss Oberkochen had also been given rights to the lens family
names, so the Zeiss Jena lenses were marked "s" for Sonnar, "Bm" for Biometar,
and "f" for Flektogon (I'm going on fuzzy memory in the case of the Flek). In
England and parts of Europe, they were allowed to use "Carl Zeiss Jena", but
still used the abbreviated family names. In still other places, they labeled
them just like they did in the Communist world. (Where Zeiss Oberkochen was not
allowed to use "Zeiss", which was everywhere at first, they used "Opton". Thus,
you'll see late 40's Rolleiflexes with Opton lenses on them.)
 
So, a Carl Zeiss Jena Sonnar might be called a "Carl Zeiss Jena s" or an "aus
Jena s" and be exactly the same lens. There is no quality difference in the
different labels and it should not enter the buying decision.
 
The Zeiss Jena Sonnar is the same formula as the Zeiss Oberkochen Sonnar and
exhibits the same qualities. The Flektogon is similar to the Distagon, and the
Biometar is a modified Planar formula just like nearly every double-gauss
normal lens made since the demise of the Tessar.
 
Carl Zeiss Jena was absorbed into VEB Pentacon at some point in the 60's, as I
recall. Pentacon also owned the Ihagee (pre-war Exakta) factory and also the
Pentacon factory that made Praktica cameras. Thus, Zeiss Jena made lenses
primarily for the Praktica camera lines. All the Jena lenses use Schott glass
just like their Oberkochen counterparts.
 
The Zeiss Jena lenses were made in four basic finishes. The first has all shiny
aluminum, often with a leather band grip on the focus ring. These were made
from about 1956 to 1963, and were all single coated. The second was black with
a hard plastic focus ring that has raised ovals on it, made from '61 to '63,
and single coated. The third type is called the "zebra" and was made from 1963
to 1967 in large quantities. They are black with alternating bands of bright
aluminum on the control rings. They are also single-coated.
 
The fourth type is all black, either painted or anodized (I have both). They
were made from 1967 to 1978 with single coatings, and from 1978 to about 1990
with multicoating. The multicoated Zeiss Jena lenses are marked "MC" with very,
very few exceptions. The black MC lenses have a mechanical slide switch to
change the lens from auto diaphragm to manual diaphram. That makes a handy
preset switch--set the aperture to what you want, focus, switch to manual, set
the exposure (or let the camera do it for you) and shoot. The lastest versions
had electrical contacts for the Praktica EE, but these are not needed by us and
should not be part of the buying decision.
 
So, the best lenses to buy are those with an all-black body marked "MC", with or
without the EE contacts, and without regard to "aus Jena" versus "Carl Zeiss
Jena" or "Sonnar" versus "s", etc.
 
Zeiss Jena built lenses primarily in two mounts (there were some old ones in the
Contax rangefinder mounts, but I'll ignore those): M42 and Pentacon Six. These
were the mounts used by VEB Pentacon, which owned Zeiss Jena. The Pentacon Six
camera was a medium format camera that was the forerunner of the Exakta 66
(which remained in production until about 1999 after being sold off to
Schneider in 1992 or so), and the lenses made for them include Flektogons in 50
and 65mm, Biometars in 80 and 120mm, and Sonnars in 180 and 300mm. All were
f/2.8 lenses except the Flek 50 and the Sonnar 300, which were f/4 lenses. The
65 was never made in the black, MC version.
 
Zeiss Jena also made lenses for 35mm Pentacon cameras, most of which were
marketed as "Praktica". They include the 35mm Flektogon and the 135mm Sonnar.
Longer Sonnars were the medium-format lenses with M42 mounts on them. The 180
is frequently available as the "Olympia Sonnar", but usually that label is
applied to an old lens. There were probably others that I have not explored--my
focus as been in the medium format area.
 
It is quite easy to get adaptors for both mounts to go on Canon EF-mount
cameras. These adaptors can be bought from DVDTechnik, at
 
http://www.dvdtechnik.com/other/adapters/adapters.htm
 
The M42/EOS adaptor is $18 and the Pentacon Six/EOS adaptor is $35. I bought all
my adaptors from them and they are reputable. (They also sell other interesting
adaptors, such as an adaptor for Nikon lenses--with manual controls, of
course--on EOS cameras). All these adaptors are non-electronic. You'll need to
focus manually, set the aperture manually, and stop it down when you meter and
shoot. Av works fine, and will set the shutter speed automatically.
 
By the way, the M42 mount originated with Pentacon and was used from the early
50's. Pentax, desiring to tap into the large number of lenses made for this
mount, used it also and made it so famous that most folks call it the "Pentax
screw mount" or "Universal screw mount". It's the same mount.
 
So, in summary, get the adaptors from DVDTechnik, and the Zeiss Jena lenses from
ebay, searching for "Jena" to sweep up both aus Jena and Carl Zeiss Jena labels,
and all the various lens families. You'll get lots of hits for binoculars and
microscopes, so filter it down to camera lenses. But the search is part of the
fun.
 
Several East German companies made lenses for the Praktica, and all were
eventually consumed by VEB Pentacon. A useful one from our perspective was
Meyer Gorlitz, though they were eventually labeled Pentacon and those are the
newer lenses we would be interested in. They made preset telephoto lenses in
300 and 500mm with interchangeable mounts. The only one worth getting is the
500/5.6 Pentacon Prakticar MC, which is multicoated, pretty fast, very big, and
VERY heavy. With a stout monopod, though, you can go shooting sports, and if
anyone laughs at you, you can kill them with it, heh, heh. They come in both
mounts, and I see them as often on ebay with the M42 mount as with the Pentacon
Six mount.
 
So, here's the list of potentially interesting lenses:
 
35mm/2.4 MC Flektogon (or "f" )
135mm/3.5 MC Sonnar (or "s" )
180mm/2.8 MC Sonnar (or "s" )
300mm/4 MC Sonnar (or "s" )
500mm/5.6 Pentacon Prakticar MC
 
The first four are labeled Carl Zeiss Jena or aus Jena.

Hallo Herr Elfman !
Leider kann ich noch nichts über den Paketdienst herauskriegen, aber ich bin dran und melde mich in Kürze wieder.
 
Mit bestem Dank und Gruß
Sutter