Re: lens tests

[Edward Meyers <aghalide@phantom.com>]

On Tue, 21 May 1996, Tom Hodge wrote:

> Mark,
> 
> Great points!  I think your comments are right on target.  In particular,
> the comments about Leica's long and well deserved reputation for perfectly
> flat film plane relationships.  I don't know whether or not their
> lens-to-body perpendicularity is any better or any worse than any other
> high-quality removeable lens camera nowdays given modern manufacturing
> methods but the film flatness thing has always been one of their fortes.
> 
> And yes, an optical bench - separating the lens totally from the camera 
> body - is the only way to evaluate one if doing a true lens test and 
> nothing else.
> 
> Rgds,
> 
> Tom Hodge
> Davidson (Lake Norman), North Carolina
> 
> On Tue, 21 May 1996, Mark Bishop wrote:
> 
> > I believe that many of the optical tests performed today are undertaken *minus*
> > the camera body, ie the lens is mounted on a rigid stage on a test bench. This
> > may discriminate in favour of those camera makers whose lens bayonets may not be
> > as flat and as accurately positioned as a Leica's or whose ability to hold film
> > perfectly flat - something which Leica Ms are reputedly very good at - is less
> > than perfect.
> > 
> 
About this film flatness thing. My spy at E. Leitz Wetzlar told me
that Leitz was impressed with the superior film flatness of the
Nikon F. Also, the Contarex, I believe is also superior to the Leica.
The idea is that both cameras have a large before and after 
film stabilizing surface.  This tends to straighten the film in the 
picture plane.
Nowadays, camera makers reduce this area to make the cameras smaller. Too
bad. Also, the Zeiss Contarex doesn't have the usual foam piece to
soften the mirror as it slams against the cage just before exposure.
To eliminate vibration Contarex mirror is "geared" to a stop. This
seems to make it noisey. But it's still a great camera. I have three
lenses and six film magazines for my spot meter Contarex.