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

["Richard Knoppow" <dickburk >]

- ----- Original Message ----- 
From: "Q.G. de Bakker" <qnu  
To: <rollei  
Sent: Thursday, May 01, 2003 4:33 PM
Subject: Re: [Rollei] Why the 6-element lens for 3.5Fs


> todd wrote,
>
> > Well, at least two of us on this list have 2.8
Zeiss-Opton Tessars on
> > Rollei 2.8 A cameras that are stinkers as far as
sharpness goes. I have
> > a 2.8 A with Jena Tessar that is tack sharp, another 2.8
A with Jena
> > Tessar that was replaced with a Zeiss-Opton Tessar that
is very soft
> > (early serial number on this camera denotes it should
have had a Jena
> > Tessar and collimator test reveals that the lens is just
plain 'ol bad)
> > and a late 2.8 A (MX model) with Zeiss-Opton Tessar that
is very sharp.
> > All cameras are in beautiful condition and have not been
tampered with.
> > So in my microcosm of 2.8 A cameras, I have exactly what
you describe of
> > the Zeiss-Opton 2.8/80 Tessar.
>
> Thanks, Todd. Usefull information.
>
> "Very sharp" vs "very soft"... I think i will continue
trying to find a way
> to clean the insides of my lenses, in the (perhaps idle)
hope that mine will
> be of the first kind.
>
> Richard's comment about the "burnished or spun-in mounting
for the rear
> component" isn't encouraging though.
> But then, maybe i don't need to remove the rear "group"?
Maybe there's
> another way in. I thin i'll keep trying (as long as i'm
confident i'm not
> doing anything irreversible).
>
> Thanks.
>
   You do not need to dismount the glass to clean it. Just
clean both surfaces. I don't know how Hassy lens mounts are
made but 35mm camera mounts often have retaining rings to
hold the back elements or groups in place. These rings don't
always have slots or dots on them, they are removed by a
tubular friction tool. The frustrating thing is that I could
probably figure it out in a few seconds if I had one to look
at.
   If a cemented component looks hazy after cleaning both
surfaces its probably the cement. Both Canada Balsam and
synthetic cements can get hazy although its more common for
synthetic cement to look this way. Shining a flashlight into
the lens will often reveal what the cause of the haze is.

- ---
Richard Knoppow
Los Angeles, CA, USA
dickburk  

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