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

[Jerry Lehrer <jerryleh >]

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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