[LargeFormat] Turner Reich Orange Filters
Les Newcomer
largeformat@f32.net
Mon Jun 4 23:40:01 2001
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