Richard Knoppow (dickburk@ix.netcom.com)
Wed, 03 Mar 1999 11:31:25 -0800
At 04:14 PM 3/2/99 -0600, you wrote:
>This is for the UK and N. Europe list members. I'd send this off list but
>I don't think I can separate the UK and Continental members from the rest
>of you.
>
>If anyone has an interest in this please contact Mr. Bluck directly. I do
>not know anything more about it than you can read below in the two quoted
>messages. I'd love to be able to salvage parts from this but it is too far
>away for me.
>
>Please remember that process camera lenses are usually optimized for around
>the 1:1 region and may not work well if you stray too far from that and
>they usually are not designed for much depth of field although they are
>very flat field. Coverage at infinity will be much reduced. They do
>arouse interesting daydreams if you see one though.
Its not quite that bad:-) Process lenes are optimised for 1:1 and, for
their intended purpose the range is around 1:5 to 5:1. For pictorial use
the loss of correction at infinity is not serious. Most process lenses are
"Dialyte" or "Celor" type, that is four-element air spaced lenses although
there some other types used. The Dialyte type, such as the
Apochromatic-Artar have corrections which are pretty stable with object
distance. They usually pick up some coma which is cured by stopping down a
bit.
By nature _all_ symmetrical lenses are optimised for 1:1, that includes
the famous Dagor. Again, the nulling of lateral aberrations will be
complete only when the _entire_ optical system is symmetrical but the
corrections will continue to very well corrected to infinity.
Even some non-symetrical process lenses were at one time widely used for
general color photogrphy, the Zeiss Apo-Tessar being one of the most
commonly used.
The coverage of process lenses is, in general, not too wide, it doesn't
have to be and a somewhat long lens tends to have better corner
illumination. The Apo-Artar at infinity focus will cover a negative whose
diagonal is equal to its focal-length when stoped down a couple of stops.
This is more than the spes say it will but they assume different operating
conditions and image requirments than are needed for general pictorial use.
I should note that there are some "wide-angle" process lenses, mostly of
the Plasmat type, made for making offset lithography plates for newspapers.
Not all of these lenses are apochromatic, they are actually more like copy
machine lenes than the older type of process lens.
There are a great many process lenses on the market now at very
reasonable prices due to the retirement of process cameras in favor of
imagesetters.
They can make very fine view camera lenses, especially for very large
format cameras.
>This is an old piece of hardware. I can't speak for the UK or European
>market but here in the US Midwest I find them on the junk piles.
>
>List minders - is an occasional posting of this sort ok?
>
>Eugene Robkin
>
>----------------------------------------------------------------------
>Hello.
> I wonder if anyone can help. I have a large format / process
>camera, and I need to find a new home for it.
> It's a Hunter Penrose 20 by 24 inch, it's complete with a
>Taylor Hobson 14 inch f9 lens, and Dalmayer air operated shutter,
>I also have about 12 feet of trackway, and the projection screen,
>(and also some film and chemistry..)
> Is there likely to be any interest in this forty / fifty
>year old hardware nowadays ? and if so, from where ?
>
>Many thanks for your assistance.
>
>the e-mail address here has now changed to
>tb@planet-tharg.demon.co.uk
>Tim.R.Bluck.
>
>-----------------------------------------------------------------------
>Hello Eugene.
> The camera, when set-up is about 12 feet long, 5 feet wide,
>and 8 feet high. It's focusing screen, and the two sets of bellows are
>in good condition. If packed for shipping overseas (ie not U.K. or
>N.Europe.) it would be about 11 X 6 X 6 feet and weigh nearly half a
>ton.
>Unfortuneately you are correct about shipping it to the 'States, the
>customs people would wonder what to make of it, and shipping somthing
>this big would be very expensive.
>There is a photographic outlet in Croydon, Surrey, called "Mr Cad" who
>have a smaller process camera without the trackway or screen going for
>1,700 pounds, so I'd guess that this one must be worth somthing. But I
>really havn't got a clue what anyone would pay for it.
>
>Many thanks for your e-mail.
>All The Best.
>Tim.R.Bluck.
>
>
>
>
>
----
Richard Knoppow
Los Angeles,Ca.
dickburk@ix.netcom.com
This archive was generated by hypermail 2.0b3 on Sat Nov 06 1999 - 10:06:54