On 2014-03-04, janders wrote:
On 3/4/2014 8:27 AM, Cydrome Leader wrote:

The precision, fit and finish of parts in older cameras is mind blowing to
me, and provides some really high standards to work towards.

My brother now has my Dad's old Zeiss Ikon Contaflex. I don't quite
recall how it operated, but basically within limits, if you changed
aperture, it would adjust shutter speed, and likewise, change shutter
speed, it would adjust aperture. All done mechanically. Boy, would I
love to see how that was done internally. And to think stuff like this
was all designed on paper, long before CAD...

I had a and use a lot a Contaflex, back in about the 1962-1964
period.

The Contaflex (and many other cameras of the period) used what
is called an "EV" (Exposure Value) scale. You lock the shutter ring and
the aperture ring together (and they move in steps of double/half light
through aperture or time the shutter is open). As far as the film is
concerned, any of those combinations is equal to all the others.
However, depth of field and motion stoppage were tradeoffs at the ends
of the range.

The shutter speeds in later cameras were weird values which were
closer to a step of two one over (1, 2, 4, 8* 15, 30, 60* 125, 250, 500,
1000) (the intervals with a '*' in them instead of a comma were where
the scale slipped a little for better numbers). The older ones were
more like (1, 2, 5, 10 25 50 100 250 500 1000) (favoring more
human-friendly numbers over closer doubling). The aperture numbers look
weirder, but since they represent the diameter (relative to the focal
length), and the exposure is more a function of the area, they also are
pretty good factor of two increases: (64, 32, 16, 8, 4, 2, 1) (with
extra half-stop values in between so you see things like 2.8, 3.5, 4.5,
11 and so on). But make the shutter speed ring and the aperture ring
lock together, and step in the proper direction (slower shutter speed
for numerically larger (thus smaller area) apertures, and the EV system
just works without any fancy mechanical coupling -- other than locking
the two rings together.

When you moved to fully interchangeable lens cameras, with focal
plane shutters, it got more difficult to couple them together like that.
The shutter was usually a curtain which traveled across the back (or up
and down with some), and the aperture being on the lens which bayoneted
(or screwed) into the body. the man thing then was a way to couple the
aperture information into the body and couple it and the shutter speed
dial to the meter. (The Contaflex only had interchangeable front
elements, and the aperture and the shutter were both built into the
stack from the body out to the front element, so the coupling was easy.
Zeiss made more serious cameras as well -- the Contax (which was fully
interchangeable, but not a SLR like the Contaflex) and later the
Contarex Super (fully interchangeable lenses *and* focal plane shutter).
I've got an old Contax, but I've never had my hands on a Contaflex
Super. The Contax was the Zeiss equivalent of the Leica (both focal
plane shutters and fully interchangeable lenses). The Japanese Cannon
started as a clone of the Leica, and the Japanese Nikon started as a
clone of the Zeiss Contax. Each camera line had leftovers from those
days for quite a while. For example the top end Nikon F SLR had the
ability to use the Contax Cassettes in place of the normal disposable
(or somewhat reusable) 35mm cassettes. It fully opened so there was no
scratching of the film through dust caught in the felt light trap as you
locked the back in place. The Contax (and the Contaflex) could use two
of them, so the film would roll from one to the other, and you could
then change between films in mid roll at the cost of a couple of frames.
The Nikon F, however, had a captive take-up spool, so you could only use
the Contax Cassette as the source, and had to rewind. Still no
film scratches from dust trapped in the light trap of a standard 35mm
cassette -- and I had a lot of those.

EV has pretty much gone away with today's cameras with built-in
metering and in many cases, control of both shutter speed and aperture
without even letting the photographer control anything (in the cheaper
point-and-shoot cameras). :-)



Enjoy,
DoN.

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