Re: [Rollei] Why the 6-element lens for 3.5Fs

[Jerry Lehrer <jerryleh >]

Peter

No comparison. BTW, the Ektar was a 5 element Heliar design
contrary to what Nordin says.  A friend of mine had Oscar Heinemann
replace the stinking 2.8 Tessar in his Rolleiflex 2.8A with the Ektar
in 1951.

Jerry

"Kotsinadelis, Peter (Peter)" wrote:

> Jerry,
>
> I klnow your affection for the Ektars, but were the Kodak Ektar on teh 'blad that good? Better than the Zeiss?
>
> -----Original Message-----
> From: Jerry Lehrer [mailto:jerryleh  ]
> Sent: Thursday, May 01, 2003 3:06 PM
> To: rollei  us
> Subject: Re: [Rollei] Why the 6-element lens for 3.5Fs
>
> Peter
>
> According to Nordin, the Tessars were supplied to the non-US
> market.  We were blessed with the superb Kodak Ektar lens.
>
> Jerry
>
> "Kotsinadelis, Peter (Peter)" wrote:
>
> > Was the Tessar for the 'blad any good? Better than the Ektar lenses they
> > were using?
> >
> > -----Original Message-----
> > From: todd [mailto:todd_belcher  ]
> > Sent: Thursday, May 01, 2003 2:22 PM
> > To: rollei  us
> > Subject: Re: [Rollei] Why the 6-element lens for 3.5Fs
> >
> > Richard, I think QG has the 2.8 Tessar in an early Hasselblad mount and
> > does not mean the 2.8 Tessar as found in the Rollei TLR.
> >
> > todd
> >
> > Richard Knoppow wrote:
> > > ----- Original Message -----
> > > From: "Q.G. de Bakker" <qnu  
> > > To: <rollei  
> > > Sent: Thursday, May 01, 2003 12:29 PM
> > > Subject: Re: [Rollei] Why the 6-element lens for 3.5Fs
> > >
> > >
> > >
> > >>Nick Roberts wrote:
> > >>
> > >>
> > >>>As an aside, has anybody ever tried the 2.8 Opton
> > >>>Tessar?
> > >>
> > >>I would love to be able to say how good/bad Zeiss-Opton
> > >
> > > 2.8 80 mm Tessars
> > >
> > >>are.
> > >>
> > >>But, alas, i haven't tested the ones i have yet, since
> > >
> > > they need cleaning
> > >
> > >>very badly. No point testing a dirty lens.
> > >>I have asked the Hasselblad Users brethren (mine are in
> > >
> > > "ancient" Hasselblad
> > >
> > >>mount) if anyone knows how to get to the rear lens group,
> > >
> > > but so far no
> > >
> > >>answer.
> > >>So maybe there is someone on this list who can tell me how
> > >
> > > to disassemble
> > >
> > >>these lenses (in such a way that they can be reassembled
> > >
> > > again)? Or knows of
> > >
> > >>any resources available anywhere that might help?
> > >>I'd be grateful for any and all assistance!
> > >>
> > >
> > >   Exactly which lens are you asking about, the f/2.8 Tessar
> > > or the Planar?
> > >   If the Tessar, there is no rear lens group, there is a
> > > single cemented component. The cell can be unscrewed from
> > > the shutter but requires some disassembly of the camera.
> > >   I don't have an f/2.8 Tessar to look at. The f/3.5 front
> > > cell has a front retaining ring which is removed with a
> > > friction tool. Probably the f/2.8 is the same. Larger
> > > Tessars, such as the 135mm, f/4.5 found on old Speed
> > > Graphics, have a threaded back cap which is easy to unscrew.
> > > Like many other lenses Tessars tend to get hazy inside the
> > > front cell.
> > >   If the back component looks hazy its probably bad cement.
> > > Recementing is not too difficult but almost all Tessar type
> > > lenses of any manufacture use a burnished or spun-in
> > > mounting for the rear component. These can not be opened
> > > without damaging them. The glass is held in place by a very
> > > thin lip which is burnished down over the lens. While they
> > > can be pried up they can never be smoothed down again. The
> > > usual method for dealing with these is to remove the lip in
> > > a small lathe and replace it with a threaded cap. Precision
> > > work.
> > >   Zeiss lenses of the 1930s and 1940s seem for the most part
> > > to have pretty good cement; I've seen relatively few with
> > > edge separation. But the canada balsam used in lenses pre
> > > about 1950 is sensitive to heat and cold and can oxidize and
> > > crystalize at the edges if the paint seal is broken.
> > >   A lot of old lenses which have low contrast are just
> > > dirty.
> > >
> > > ---
> > > Richard Knoppow
> > > Los Angeles, CA, USA
> > > dickburk  
> > >
> > >

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