[LargeFormat] Double Protar Lens

[LNphoto]

>
> Thanks for all the replies.
>
> It seems that my confusion lay in the fact that the lens is in a 
> shutter with two aperture scales. I do not have the beast yet, but it 
> seems to be a single 11" approx. Series VII - ie half a double Protar, 
> probably placed in the shutter some time after its 1895 manufacture. 
> More than likely it is f12.5
>
> I have a Ross Double Protar that is a 10" f7 with 16 1/2" and 19 3/4" 
> cells at f12.5. It's engraved with a flowing script: "Zeiss 
> Convertible Anastigmat". Cleaned it up a couple of months ago and when 
> the new multi-lens board with Packard is set up will shoot some film 
> with it. It does seem as though it'll fit front mounted on a Betax #5 
> shutter so I may get around to making a sleeve up for it..... In any 
> case, the new Bausch and Lomb lens may be a direct fit in the Ross 
> barrel so there could be a few more focal lengths available.
>
> Many of these older lenses have the patina of use - from the wear of 
> the brass lens barrel, the Ross looks as though it was lovingly used 
> for many decades, possibly from an old pro. studio locally. If we 
> could only see some of the photos made with it.....
>
> Cheers,
>        Clive
>


According to my 1911 catalog, a pair of 11 3/16" cells give a combinded 
focal lenght of 6 3/8" @ f6.3 and covers 4 1/2 x 7 1/4.  Something 
tells me in later years that was rounded to 5x7.    The 11 3/16" cell 
alone will cover 6x8 (whole plate) and has a back focus of 12 7/16".

I have a couple of B&L double protars....enough to make a D set.  I 
also have C+ set from Zeiss.   While the glass may be similar, you have 
to remember these were made with "native" machines.... The Zeiss is 
metric through and through,  The B&L is Yankee.  The Ross may be 
"stricken" with Whitworth threads, so that tube may need different 
threads at one end than the other.

Les