[LargeFormat] Double Protar Lens

[LNphoto]

Lenses in Photography
His chapter in Photographer's Handbook by Henny and Dudley
and History of the Photographic Lens


These are in ascending order..... The Photographer's handbook chapter 
is a table listing hundreds of lenses by type and size. It's great for 
figuring out that a Celor is essentially an Artar, or that there were 
many many companies making the tessar design. History of the 
photographic lens, is more of a story telling who designed what lens 
before the other guy, and why this lens was designed that way to get 
around this patent.
On Friday, September 5, 2003, at 07:18  PM, Ken Strauss wrote:

> You frequently refer to Kingslake's book. I have his "Lenses in 
> Photography"
> but he published many others; which do you find most useful?
>
> -----Original Message-----
> From: largeformat-admin@f32.net [mailto:largeformat-admin@f32.net] On 
> Behalf
> Of Richard Knoppow
> Sent: September 5, 2003 17:22
> To: largeformat@f32.net
> Subject: Re: [LargeFormat] Double Protar Lens
>
>
> ----- Original Message -----
> From: "Clive Warren" <Clive.Warren@megacycle.co.uk>
> To: <largeformat@f32.net>
> Sent: Thursday, September 04, 2003 3:38 PM
> Subject: Re: [LargeFormat] Double Protar Lens
>
>
>> At 17:31 04/09/2003 -0400, LNphoto wrote:
>>> A pair of 16 1/16" make for a 9 1/4" focal length that
> covers 6x8 wide
>>> open and 8x10 at "smaller stops" usually f22
>>>
>>> I gotta check other sources on the lettered sets.
>>>
>>> the 16" Was part of the D set and in it's "normal" mount
> is probably the
>>> same as the 18" cell.   The pair of 11" lenses are
> probably in a smaller
>>> mount than the 16.
>>>
>>> So the 11" cells are US system.  That's unusual, at least
> here in the
>>> States.   For the most part US system had been cast aside
> like a DAT tape
>>> or a laser disc by WWI.  Maybe it hung on later over
> there.
>>>
>>> Les
>>
>> Les,
>>
>> Thanks for that - a bit longer combined FL than
> anticipated. Not too much
>> in the way of movement on 8x10 then... at least it covers.
> It may end up
>> being used on 5x7. Will keep my eyes open for the longest
> D set focal
>> length cell.
>>
>> The 11" cells are Bausch and Lomb so originate in the USA.
> From the 1958
>> edition Focal Press Encyclopedia, The US system was
> proposed in 1881 by the
>> Royal Photographic Society and was not much used in
> Britain or 'on the
>> continent' <grin>  '......but it was used for some time in
> America,
>> particularly on earlier Kodak cameras'. p.349 Vol. 1.
>>
>> If we suppose that the lenses were made from 1895 (the
> patent date) then
>> quite a few would have been made by 1914 as they were one
> of the best
>> lenses available until around the early 1920's.
>>
>> So it seems that we (UK) didn't always adopt new systems
> after you guys had
>> already rejected them and moved onto something better :-)
>>
>> Cheers,
>>             Clive
>>
>>
>    B&L seems to have been the main user of the US system of
> stops. It is found mainly on B&L Rapid-Rectilinear lenses
> and can be found on those made up to the early 1930s!
>    Shutters for some Protar sets are calibrated in mm rather
> than f/stops. You can tell these easily because the numbers
> get smaller as the aperture gets smaller.
>   Without digging out Kingslake's little book on Rochester,
> N.Y. photographic companies I can't be sure of the date of
> the agreement between B&L and Zeiss but by memory it
> predates 1900. Its possible some early Protars were
> calibrated in US stops.
>   BTW, a number of stop systems were proposed in the late
> 19th century, mainly in an attempt to show some direct
> relationship to either light gathering power or to exposure
> time. None was very successful. I think the US system was
> the only one to get much use. Zeiss had at least two systems
> but they were used almost exclusively on lenses sold in
> Germany.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@ix.netcom.com
>
>
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