Re: Coverage of 127mm Ektar?

[dickburk@ix.netcom.com (Richard Knoppow)]

cocam@cableinet.co.uk wrote:

>Dear All,
>
>Does anyone know the coverage of a 127mm Ektar in Supermatic at inifinity? 
>Have one of these on a Speed Graphic recently acquired and guess that it will
>just cover 4x5 with no movements.
>
>Seem to recall having read somewhere that these lenses were designed for 2x3
>rather than 4x5.  This may result in an image circle that may well cover 4x5
>however the edges of the image on 4x5 may not be too sharp even when stopped
>down.
>
>Has anyone had experience with this lens?
>
>All the best,
>
>               Clive    http://clive.bel-epa.com
>
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  They were designed for 3-1/4 x 4-1/4. It covers 4x5 and is pretty
sharp in the corners when stopped down to f/16. This was one of the
standard lenses used on 4x5 press cameras. The coverage is about 65deg
at infinity and f/22.
  It is a remarkably good lens, well corrected for coma and having
nearly no lateral color. 
  Most of these old Ektars have gotten hazy inside which can make them
look soft. The haze can be cleaned off by removing the front element.
This is done using a ring of sticky rubber and a round tool, a bottle
cap the right size will do. The haze comes off with regular lens
cleaner. When clean even the early un-coated lenses are surprizingly
contrasty. Shining a flashlight through the lens will show up the haze
and any other blemishes or damage the lens may have.  Kodak used
synthetic cement on the rear elements. This is much longer lived than
the Canada Balsam mostly used at the time but can start to degrade.
The flashlight test will show this also. The rear element should look
completely clear. If the cememt layer has started to go it will look
slightly hazy or diffuse. That will cause the lens contrast to be low
even before it starts to affect the sharpness. I haven't seen too many
Kodak lenses with this problem but it should be looked for.
---
Richard Knoppow
Los Angeles, Ca.
dickburk@ix.netcom.com