Re: [Rollei] 2.8 Tessars and 3.5 F - 12/24 function

[Nick Roberts <nickbroberts]

Todd,
Thanks for that - I was always confused about the
Zeiss Jena Tessar/ Zeiss-Opton Tessar before, now it's
very clear (previous explanations I had seen elsewhere
got confused with the 2.8B lens, which I knew was
wrong). Thanks everyone else for pointing out the
heritage of the 2.8 Tessar - it hadn't occurred to me,
yet I've always liked the Super Ikontas.

I really knew about the 12/24 issue (thanks to reading
it here first, probably) - I just had it fixed in my
mind that my Planar 3.5F was a similar vintage to my
Xenotar ones, and that they were all pretty early - so
5 element lenses. If it hadn't been for this
discussion, I would still be none the wiser. It
doesn't affect what I think of the lens (wonderful for
B&W), but it is nice to know.

It's also intriguing that with the reported quality
control tests there were so many problems - I can but
assume (again!) that the QC was stepped up as a result
of these issues - I know I've read of customer
critisim of all the lenses on the A and B.


Nick

- --- todd <todd_belcher  > wrote:
> Nick,
> 
> There were two Tessars on the 2.8 A - a Zeiss Jena
> Tessar, and a 
> Zeiss-Opton Tessar (there is no such thing as an
> Opton Tessar).
> 
> I have tried both. Results were varied. The Jena
> Tessars on the 2.8 A 
> are prewar lenses that Zeiss coated for Rollei for
> inclusion on the 2.8 
> A. some of these lenses were mismatched and produced
> poor results. 
> Others of these lenses were perfectly fine.  Rollei
> then switched to the 
> Zeiss-Opton Tessar for the rest of the 2.8 A cameras
> and would swap Jena 
> Tessars for Zeiss-Opton Tessars when cameras came in
> for repair.
> 
> Interestingly, my 2.8 A with Jena Tessar is sharp as
> a tack. But the 
> Zeiss-Opton Tessar is soft. I have checked the lens
> on a collimator and 
> there is nothing amiss there - the lens is just a
> dud with very poor 
> resolution.
> 
> Regarding 12/24 and Planar lenses. All 3.5 F cameras
> can be converted to 
> 12/24. It is just that those made after about 1966
> had much of the 12/24 
> mechanism already installed in the camera meaning
> that conversion was  a 
> reasonably simple matter. 3.5 F (and 2.8F) cameras
> before this date 
> require the whole transport mechanism to be swapped
> for an upgraded one 
> - a much larger job. So 12/24 is no indicator of a
> Rollei F camera's age.
> 
> I was afraid that someone was going to ask when the
> 3.5 Xenotar was 
> modified. I have absolutely no idea with any
> accuracy.
> 
> todd
> 
> 
> 
> Nick Roberts wrote:
> 
> > I have several times heard the story that some of
> the
> > original 5 element Planars were incorrectly
> assembled
> > with an element reversed - now is that an old
> wives'
> > tale (as I'm inclined to believe) or is it true?
> If
> > so, it could explain a 50% batch rejection rate.
> > 
> > As an aside, has anybody ever tried the 2.8 Opton
> > Tessar?
> > 
> > As another aside, I was convinced my Planar-ed
> (and
> > unmetered) 3.5F was a 5 element lens - I had
> always
> > assumed that because it wasn't a 12/24 model it
> would
> > be too old (yes, I know about assumptions!) and
> only
> > checked the serial numbers of cameras and lens
> this
> > morning (and the lens coating colour). The
> interesting
> > point is that this 6 element lens does not
> outperform
> > my (I assume!) 5 element Xenotars - there's a
> touch
> > more contrast, and a different colour balance, but
> > neither newspaper nor brick wall tests can
> separate
> > resolving power, even at the edges. Whilst this is
> in
> > no way a scientific test, it does make me wonder
> if
> > there really is a performance hike with the 6
> element
> > lens, or if indeed it was to simplify production.
> > 
> > As a final aside, when was the Xenotar modified?
> > 
> > Nick
> > 
> > __________________________________
> > Do you Yahoo!?
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> > 
> 
> 


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