[rollei_list] Re: Back-Focus and Retro-Focus ...
- From: "Eric Goldstein" <egoldste@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Fri, 11 Jul 2008 09:35:22 -0400
Hi Carlos -
Yes, this has been covered earlier in the thread. In fact, the Zeiss
Tessar for Contax SLR is a 45mm!
Eric Goldstein
--
On 7/11/08, Carlos Manuel Freaza <cmfreaza@xxxxxxxxxxxx> wrote:
> Yes Eric, we agree on the point, I'd add that those issues are about normal
> design 80mm lenses with five elements, mirror issues were not and are not a
> problem for Tessar type 80mm four elements lenses (6x6 format) or for 50mm
> four element 50mm lenses (35mm format).
>
> Carlos
>
>
> --- El vie 11-jul-08, Eric Goldstein <egoldste@xxxxxxxxx> escribió:
>
> > De: Eric Goldstein <egoldste@xxxxxxxxx>
> > Asunto: [rollei_list] Re: Back-Focus and Retro-Focus ...
> > Para: rollei_list@xxxxxxxxxxxxx
> > Fecha: viernes, 11 de julio de 2008, 9:49 am
>
> > Hi Carlos -
> >
> > OK, sounds like we agree that a 90 mm lens does not have
> > the back
> > focus/clearance issues an 80 mm lens does when hanging on a
> > 66 SLR
> > (the crux of this discussion) and yes, interesting how
> > Praktica and
> > other lower end makers solved this engineering problem
> > inexpensively
> > while maintaining some quality...
> >
> >
> > Eric Goldstein
> >
> > --
> >
> > On 7/11/08, Carlos Manuel Freaza
> > <cmfreaza@xxxxxxxxxxxx> wrote:
> > > --- El jue 10-jul-08, Eric Goldstein
> > <egoldste@xxxxxxxxx> escribió:
> > >
> > >
> > > > Very interesting information, Carlos. It is
> > important to
> > > > note that this lens:
> > > >
> > > > http://araxfoto.com/lenses/vega-12/
> > > >
> > > > is badged a 90mm/2.8, which is important to the
> > issue at
> > > > hand.
> > >
> > >
> > > The Vega-12b 2.8/90 was the standard lens for the
> > Salyut MF camera, the Salyut was the original Hasselblad
> > 1600F/1000F copy, the Kiev 88 is an improved Salyut and the
> > Kiev 88 uses an Arsenal/Arsat/Volna 2.8/80 five elements
> > lens, but the Vega 90mm can be used like the standard lens
> > too.
> > > The standard lens for the Hasselblad 1000F was the
> > EKTAR (Eastman Kodak TessAR)2.8/80, a four elements lens,
> > no problem with the mirror, this camera could only offer a
> > 60mm lens like wide angle lens (no "retrofocus"
> > design) due to the mirror movement issue.
> > > The new 1957 Hasselblad 500 C (Compur) with built-in
> > leaf shutters for the lenses required to re-calculate the
> > 2.8/80 five elements Planar (not used for the 1000F) and
> > then the seven elements Planar 2.8/80 was built and the
> > retrofocus design allowed new and shorter wide angle
> > lenses.
> > > I think eastern Europe MF SLR camera manufacturers
> > managed the standard lenses and cameras construction (as
> > John Wild suggested) to use cheaper five elements standard
> > lenses, even adding 10mm for the focal length like the Vega
> > Lens and the Salyut camera sample but maintaining the lens
> > quality regarding the western Europe and Japan MF lenses,
> > the Carl Zeiss Jena lenses specially.
> > > If you don't have a lot of cameras and lenses
> > measurements to compare and the knowledge to interpret
> > them, it's almost impossible to obtain a definitive
> > conclusion, but since the evident lenses construction
> > differences are for standard lenses only, we are talking
> > about a few mm that some slight design and construction
> > differences could explain.-
> > >
> > >
> > > Carlos
> > >
> > >
> > >
> > >
> > >
> >
> ____________________________________________________________________________________
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