[LargeFormat] Ross lens, Epsilon shutter

[Clive Warren]

At 8:43 pm +0100 20/4/02, Martin McCarthy wrote:
snip
>But I know pretty much nothing about the lens that came with it.  The
>text around the glass reads:
>"5in wide angle xpress f4.5 No 2059 Ross, London"
>and it is in an Epsilon shutter, speeds 1s to 1/250 and B and T.
>
>The only reference I can find to this lens on the web is on the MPP
>users' page, so I wonder if this originally came from an MPP camera
>rather than the Speed Graphic.
>On the other hand, the plate that gives the table of shutter speeds
>based on Curtain Aperture/Tension Number says: "Colwood Camera Co (1953)
>Ltd, Authorised Graflex Distributors, London, SW19", so maybe it is a
>normal lens for Speed Graphics that were distributed here in the UK.

In general the Ross Xpress lens have a good reputation they are well 
corrected Tessar designs with a rear cell comprising three elements - 
I have a 13" Xpress lens here in barrel that is waiting to be tried 
out on 8x10. The 5" WA Ross Express is a good lens and the Epsilon 
shutter was used by a number of suppliers in the UK including MPP. In 
the early 50s the 5x7 Kodak Specialist Model 2 was usually supplied 
with a Kodak Ektar 203mm in an Epsilon shutter. I found some words of 
wisdom from Richard Knoppow that states the lens has an 80 degree 
coverage.

The information I have gives the angle of coverage of these types of 
lenses as between 65 and 70 degrees.


Richard says that:

"...the lens is a Plasmat, similar to the modern Schneider Symmar and 
the Rodenstock Sironar.  It was made for use on aerial cameras and 
generally has a good reputation.  The only problem is that it has 
eight glass-air surfaces and suffers from flare if not coated."



The WA Express is similar to the Zeiss Orthometar and the Bausch and 
Lomb Altimar - Taylor and Hobson also produced a similar lens. These 
lenses were competitors to the famous Metrogon used for aerial 
surveillance during WWII. The Metrogon has a 90 degree angle of 
coverage!

I have a lens diagram here that shows six elements with a front pair 
and a rear pair cemented giving eight air to glass surfaces as stated 
by Richard. British patent date August 16th 1928.

So, the Xpress WA should perform well unless you include a bright 
light source in the frame.

I would imagine that a lot of these lenses found their way into the 
civilian photography market after the end of the WWII. They would 
have been excellent quality and a good choice for the amateur 
photographer in the austere conditions that prevailed at that time.

Hope this helps,

Cheers,
        Clive