[LargeFormat] Turner Reich Orange Filters

[Clive Warren]

At 20:38 04/06/01 -0700, Les Newcomer wrote:
>Clive Warren wrote:
> >
> > Hardly an APO lens - however apparently capable of excellent performance as
> > they are a protar design with an additional element to avoid being sued I
> > guess .......
> >
>
>That's what I've heard from Ken, Don Cardwell and Kingslake. The 5
>cemented elements created two problems. For  added  cemented surface,
>you increased the likely hood of all elements not being concentric by at
>least a magnitude. This made assembling a TR accurately painfully
>difficult and I suspect quality control got a bit lax from time to time.
>
>Second, some of the surfaces were fairly strong curve. This put greater
>strain on the balsam at the edges--which is why you rarely see a perfect TR
>
>Les

Thanks for the additional information - seem to recall Ken saying that he 
had recemented loads of these lens and that he had a very high opinion of 
them when they are used correctly.  There are all sorts of legends 
circulating about the Turner Reich lenses, however what you say about 
quality control must be true as there is plenty of variability in 
contemporary lens performance......

If the quality control problems were with grinding the lenses then any 
amount of careful assembly in cementing the elements together would not 
have helped....

I have reminded Ken about the existence of this list and hope he has the 
time to join up and tell us more - particularly about the Wratten 
equivalent of the original T-R orange filter which is what I was trying to 
find out.

Cheers,
             Clive