Re: [Leica] Effective Base-Line

[Dante Stella <dante@umich.edu>]

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You raise an interesting point.  Leitz, if anything, seemed pretty =
conservative - their actual baseline, which I think was 40mm or so, =
would have been sufficient on its own (i.e. without magnification) to =
focus all but maybe 2 or three LTM lenses (Hektor, Thambar, and =
Summarex, and even then they might have worked).  When Canon went into =
LTM with combined finders, it looks like all they did was build a finder =
around that actual baseline.  Same with the early Soviet product.  (or =
is that produkt?)


Contax was just from a different world... far ahead of its time, very =
over-built and very tough.  The Ektra was something from Area 51 - too =
far ahead of its time.


Zeiss-Ikon did some weird stuff with the Super Ikonta Cs, which probably =
couldn't be focused accurately without the extra magnification, since =
their actual BLs were very, very short for a 105/3.5.  The Moscow-5 I =
had had a 100% RF, but spread out over a bigger distance (if I recall) =
to make up for that.  The RF on the Super B was a work of pure genius.  =
Too bad they didn't have today's multicoated prisms and better =
beamsplitters to do it.


On Thursday, October 5, 2000, at 10:13 PM, Marc James Small wrote:

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<italic></italic></color><italic>Hmm.  I understand that effective =
base-line IS a real factor.  That is, =
a</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>real base-line of 10cm magnified at a =
power of 1.5X should be =
APPROXIMATELY</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>equal to a real base-line of 15cm.  =
Certainly, Leitz felt so in =
their</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>design of the later LTM cameras, with =
their magnified RF's.  I have =
always</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>found the IIIc and later RF easier to =
use than the later M's due to =
this.</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>It is more accurate in =
practice.</italic><color><param>0000,0000,0000</param>


<italic></italic></color><italic>But, of course, the LONG baselines on =
some of these cameras is =
quite</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>interesting.  The Kodak Ektra had a =
real base-line of 105mm, and the =
early</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>Contax I's had an effective base-line =
of 92.7mm.  By comparison, the =
later</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>LTM cameras only had an effective =
base-line of 57mm.</italic><color><param>0000,0000,0000</param>


=
<italic></italic></color><italic>Marc</italic><color><param>0000,0000,0000=
</param>



=
<italic></italic></color><italic>Marc</italic><color><param>0000,0000,0000=
</param>


<italic></italic></color><italic>msmall@roanoke.infi.net  FAX:  =
+540/343-7315</italic><color><param>0000,0000,0000</param>

<italic></italic></color><italic>Cha robh bas fir gun ghras =
fir!</italic><color><param>0000,0000,0000</param>