[LargeFormat] Ross lens, Epsilon shutter

[Les Newcomer]

> From: "mark blackman" <mark.blackman1@btinternet.com>
> Reply-To: largeformat@f32.net
> Date: Sun, 21 Apr 2002 09:49:13 +0100
> To: <largeformat@f32.net>
> Subject: Re: [LargeFormat] Ross lens, Epsilon shutter
> 
> I have a Wray 135mm f 4.8 Lustrar lens mounted on an Eplsilon shutter (B, T,
> 250 - 1 sec) which I use on a Crown Graphic (serial no: 916034)
1956 (hint hint, nudge nudge  ;)

& I'm
> pleased with it's operation. Not sure how this compares with the 5" WX
> Xpres.
> 
> ----- Original Message -----
> From: "Clive Warren" <cocam@blueyonder.co.uk>
> To: <largeformat@f32.net>
> Sent: Sunday, April 21, 2002 9:06 AM
> Subject: Re: [LargeFormat] Ross lens, Epsilon shutter
> 
> 
>> At 8:00 am +0100 21/4/02, philip.lambert wrote:
>> snip
>>> supplied German needs at the time?) The 5" WA Xpres probably replaced
>>> imported  LF lenses like Xenar and Ektar. Wray also made LF lenses for
>>> British MPP then. (avoid their 89mm).  I should guess it had an extra
>>> element for the added corrections needed to allow f4.5 on a widefield
> lens
>>> unless you were expected to stop down a lot. The Epsilon shutter was said
> to
>>> be unreliable but mine never played up. Does it have a standard coax
> socket?
>>> Some had a non-standard socket.  Philip
>> snip
>> 
>> Philip,
>> 
>> The Xenar would not have had the coverage nor corrections required
>> for aerial photography. The Aero Ektar lenses came along much later
>> and were used by the UK for aerial surveys during WWII, probably
>> supplied under the "Lease Lend" scheme and came over on Liberty ships
>> in the early days. Michael Briggs probably knows  a lot more about
>> the history.
>> 
>> In my post I was referring to two main types of lens, the standard
>> Xpres and the WA Xpres. These are very different in design and
>> intended purpose.
>> 
>> The standard Tessar type design of Xpres lens includes an additional
>> element in the rear cell probably to avoid infringing the patents on
>> the Tessar design rather than adding huge amounts to the performance
>> of the lens.
>> 
>> The WA Xpres is a different design - ie a Plasmat rather than a
>> Tessar. The Plasmat is a superior design in terms of correction of
>> aberrations across the whole field of coverage and the WA Xpres was
>> designed to be used for aerial photography where such accuracy was
>> important for survey purposes.
>> 
>> The standard Xpres lenses have a great reputation and I am looking
>> forward to trying mine out - it is a brass 13" APO Process Xpress f9
>> so is compact and may make a good field lens on the 8x10.
>> 
>> Cheers,
>> Clive
>> 
>> _______________________________________________
>> LargeFormat mailing list
>> LargeFormat@f32.net
>> http://www.pairlist.net/mailman/listinfo/largeformat
> 
> 
> _______________________________________________
> LargeFormat mailing list
> LargeFormat@f32.net
> http://www.pairlist.net/mailman/listinfo/largeformat