[LargeFormat] Ross lens, Epsilon shutter
Clive Warren
largeformat@f32.net
Sat Apr 20 16:38:01 2002
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