[rollei_list] Re: Do you know?

  • From: Carlos Manuel Freaza <cmfreaza@xxxxxxxxxxxx>
  • To: rollei_list@xxxxxxxxxxxxx
  • Date: Sat, 10 Jan 2009 05:16:47 -0800 (PST)

Hi Frank:
          Yes, BTW you are right, it was the reason the only camera that had 
success competing with Leica was the Zeiss Ikon Contax, it was as good as Leica 
about construction quality and better than Leica about several technical 
solutions.It's a pity for the photographic industry the WWII caused major 
damages to Zeiss Ikon AG and Carl Zeiss Jena altering the Contax RF cameras 
evolution. A 300 mm rangefinder wouldn't be good if a mirror has an uneven 
surface (and it would be difficult to focus sometimes due to the images 
separation could be large too much).

Carlos



--- El sáb 10-ene-09, Frank Dernie <frank.dernie@xxxxxxxxxxxxxx> escribió:

> De: Frank Dernie <frank.dernie@xxxxxxxxxxxxxx>
> Asunto: [rollei_list] Re: Do you know?
> Para: rollei_list@xxxxxxxxxxxxx
> Fecha: sábado, 10 de enero de 2009, 7:45 am
> Hi Carlos,
> One has seen several comments about rangefinder base length
> over the years. It is certainly an important aspect for
> potential rangefinder accuracy but the precision to which
> all other parts are made, such as the lens register to film
> plane accuracy, lens mount to focusing cam accuracy, and the
> precision of the internal mechanical parts linking the lens
> focus movement to the optics of the rangefinder are equally
> important.
> The classic example of getting this wrong is the Kodak
> Ektra. This has a huge rangefinder base but the mechanism
> connecting it to the lens movement is pitifully inadequate
> and prone to wear such that it is extremely unlikely for a
> used Ektra to be nearly as accurate in focussing as a Leica,
> despite the potential of the rangefinder base.
> Frank
> 
> 
> On 9 Jan, 2009, at 08:50, Carlos Manuel Freaza wrote:
> 
> > I think the word "telescope" was confusing
> Richard, however later Leica SM models have viewfinders with
> 1.5x magnification, being the baseline physical length about
> 38mm x 1.5= 57mm for the effective baseline, shorter than
> the Contax II effective baseline clearly, anyway a good
> effective baseline for focusing.
> > I have the book "35 MM Photo Technique" by
> H.S. Newcombe, it shows the Contax and Leica SM and Ektra
> rangefinder designs, they are pretty different (the Ektra
> has a "split field" RF type).The author writes the
> cameras physical baseline length only, not the effective
> baseline. The two wedges in the Contax RF are significant to
> keep the RF calibration even for worst situations.
> > 
> > An interesting comparison about the new Zeiss Ikon RF
> and Leica M7:
> > 
> > Zeis Ikon RF
> > 75mm x 0.74 magnification with an effective length of
> 55.5mm
> > 
> > M7:
> > 69.25mm x 0.72 magnification, with an effective length
> of 49.9mm.
> > 
> > "...prewar Contax of Zeiss Ikon AG were always
> superior to Leica. Indeed, the Contax was known, thanks to
> its long rangefinder baseline, for the highest accuracy in
> measurement of object to camera distance for precise
> focusing." (Shutterbug, S.Takeda, April 2005)
> > 
> > Carlos
> > 
> > 
> > 
> > --- El jue 8-ene-09, Richard Knoppow
> <dickburk@xxxxxxxxxxxxx> escribió:
> > 
> >>    Well, you are right, I just looked again. The
> range
> >> finder image is larger because it is life-size
> while the
> >> viewfinder has some reduction in size.
> >>    While the Contax has metal slats in the shutter
> I am
> >> not sure it is safe to point it at the sun due to
> the cloth
> >> ribbons that hold the slats together. Even an
> all-metal
> >> shutter curtain such as the one used in Nikon F
> cameras is
> >> probably not immune to sun damage. Of course, in
> an SLR with
> >> an automatic mirror return the shutter is exposed
> to the
> >> outside world only briefly so it isn't really
> >> comparable.
> >>    As far as noise, I don't know of any focal
> plane
> >> shutter which is as quiet as a Compur shutter.
> >> 
> >> --
> >> Richard Knoppow
> >> Los Angeles, CA, USA
> >> dickburk@xxxxxxxxxxxxx
> >> ---
> > 
> > 
> > 
> >      Yahoo! Cocina
> > Recetas prácticas y comida saludable
> > http://ar.mujer.yahoo.com/cocina/
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