[rollei_list] Re: "different types of black boxes" (was: OT / prove it !)
- From: Nick Roberts <nickbroberts@xxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Sun, 3 Apr 2005 15:00:17 +0100 (BST)
--- Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
>
>
> -----Original Message-----
> From: Nick Roberts <nickbroberts@xxxxxxxxxxx>
> Sent: Apr 3, 2005 1:34 AM
> To: rollei_list@xxxxxxxxxxxxx
> Subject: [rollei_list] Re: "different types of black
> boxes" (was: OT / prove it !)
>
>
> But the Contax and Leica shutters did NOT have equal
> performance. The Contax shutter was capable of
> 1/1250
> - the first FP Leica shutter managed 1/500, I think.
> It is generally accepted that Leica lenses were
> inferior to Zeiss until the mid-50s introduction of
> rare earth glasses. In my personal experience, the
> Jupiter 12 Biogon copy is every bit as good - and
> faster - than my 35mm f3.5 Summaron - and that's a
> pre-war design, manufactured under lower QC
> conditions, against a 50's design. Mind you, the
> Summaron is beautifully compact, and the Jupiter
> doesn't fit on the Contax IIIa.
>
> Nick
>
> The maximum speed is not really an issue. This
> was a sales point only and Leica was able to
> increase the top speed to 1/1000th easily. It is
> also doubtful if the Contax shutter actually ran at
> 1/1200th.
Agreed, but my point was that the complicated design
of the Contax shutter was to cope with the 1/1250
issue - not required on the Leica shutter.
> The Leica shutter is a very elegant bit of
> machery. It consists of two independant curtains, an
> opening curtain and a closing curtain. They run at
> constant speed. What is changed to change the speed
> is the delay between starting the opening curtain
> and opening the closing curtain. The delay results
> in a slit of varying length. The delay is controlled
> by the position of a pin on a disk. The position of
> the pin is set by the speed control.
> Because both curtains tend to accelerate as they
> run a brake is used on the closing curtain. This
> slows it down a little resulting in the length of
> the slit increasing a little as it runs across the
> film. When this is adjusted right the result is
> constant exposure across the film.
> The Contax shutter runs in the sort direction of
> the film which allows it to run slower for a given
> slit length to get the same speed. The curtain has
> two parts but they are tripped together. The speed
> adjustment locks the two parts together for a given
> slit length. The actual exposure is controlled by
> clock work escapements. There are three separate
> excapements to control the speed over the full
> range.
Indeed - which is the clever bit that theoretically
allows for a faaster top speed.
> Contax also made much of having a metal shutter
> curtain. It is more immune to burning from
> accidental exposure to the sun than the Leica
> shutter, which is made of rubberized silk. The
> Contax shutter is only partly metal. It is made of a
> series of narrow segments hinged together along
> their width and held the long way by a ribbon of
> silk on either side. This doesn't sound very rugged
> but seems to have been quite the converse.
> The Contax shutter, AFAIK, was never duplicated
> in any other camera.
Unless you count the Kiev clones.
>The Leica shutter has been used
> in numerous 35mm cameras in various forms. The
> shutters in the Exakta, Ektra, Nikon, Nikon F,
> Cannon, many others are based on the Leica shutter.
> The Nikon F, BTW, has an actual metal shutter, the
> curtains are made of Titanium. With the exception of
> the Copal Square shutter, a sort of multiple blade
> focal plane shutter, nearly all moden 35mm cameras
> use some variation of the Leica shutter.
Have you ever seen a Kiev 10 or 15 shutter? Wonderful
pieces of art! They are something else.
>The
> increase in maximum speed in these cameras is mostly
> due to the use of superior materials for the
> curtains. The Copal Square shutter is also capable
> of very high speeds, probably higher than any
> curtain type shutter.
>
> As far as lenses, its difficult to know. Leica's
> first lens was a variation of the Tessar, marketed
> as the Elmar. The biggest difference between the
> Elmar and Tessar is that the Elmar had the stop in
> the front air space. This probably makes no
> difference whatever in performance. This is the lens
> that established Leica's reputation for sharpness.
> The original Contax lens was also a Tessar but Zeiss
> rapidly came out with faster lenses. I have a
> suspicion that the f/1.5 Sonnar was subjected to
> strict QC at the factory to make sure they worked up
> to specs. There was also an f/2 Sonnar, with one
> less element. It would be interesting to test good
> samples of these lenses. Zeiss also offered some
> very advanced designs for Contax such as the early
> Biogon wide angle lens. In this respect I think
> Zeiss was ahead of Leitz. The Zeiss vs: Leitz
> argument is one that dates back as far as the
> cameras. One would have to test the lenses on a
> bench to get any real proof one way or the other.
>
True. But the majority of user opinion is in favour of
Zeiss, I believe.
> I think both cameras were remarkable, they both
> offered very good design and excellent manufacture
> quality. And, of course, both were dreadfully
> expensive.
Absolutely.
> As an after thought It has always been
> interesting to me that none of the traditional 35mm
> camera manufacturers forsaw the great impact that
> SLRs would have. Even though Exakta was the first,
> or certainly one of the first to offer SLR's they
> didn't refine the design. It was really Nikon who
> established the 35mm SLR as a popular standard. Both
> Zeiss and Leitz were very much latecomers to the
> field.
>
Unless you count the Contax S, of course.
>
>
> --
> Richard Knoppow
> dickburk@xxxxxxxxxxxxx
> Los Angeles, CA, USA
>
Very rare that I apparantly disagree with you so much,
Richard - but remember, I do prefer the Leica to the
Contax. ;)
Nick
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