280mm series V.B. Cooke Process Anastigmat Lens

[laz]

I could just ask Jim Gallie but......

Before I became really serious about LF I was knocking around on ebay and on a whim bid a huge definantly non-field 8x10 that, if good for nothing else it, came with a couple of dozen 5x7 and 8x10 film holders I figured were worth more than the camera. (of course once I had the holders I had to have a 8x10 field didn't I ?)

Anyway it came with a 280mm series V.B. Cooke Process Anastigmat Lens. I was looking at it this morning and saw that it has an ajustable slit on the barrel between the elements. As a LF newbie I'm baffled. What is it for?

Thanks,
Bob

 

[Dan Fromm]

Many process lenses have such a slit. It is adjustable so that it can be closed (to exclude light) when not in use. The slit accepts a variety of Waterhouse stops.

 

[Denis P.]

Heh, I wanted to write something completely different, guessing about Waterhouse stops or miissing diaphragm lever, but here's what it is - straight from the horse's mouth:

"Cooke process lenses made after the early 1920s were provided with a removable lens-hood that could be covered with a leather cap. The screw thread that attaches the hood could alternatively receive any process prism fitted with the standard screw. Process Prisms are extremely rare now and are the stuff of museums instead of Ebay. An iris diaphragm was provided at that time instead of the stops with circular openings. A narrow slot in the lens barrel near the front of the lens could receive process diaphragms or gel filters (of graphic arts quality) if desired. The slot can be opened and closed by revolving the inscription tube."

- cited from:

http://www.cookeoptics.co.uk/cooke.nsf/press/viewcamera2002

HTH,

Denis

 

[laz]

or gel filters (of graphic arts quality) if desired. The slot can be opened and closed by revolving the inscription tube."

Thanks Denis! That fits prefectly with what I believed the camera to be, a commercial copy camera.

I'd been to the Cooke website before but never saw the tidbit you quoted

Soon I'll plunk that puppy onto the Korona and see what image it produces for me.

-Bob

 

[jimgalli]

An educated guess is it won't cover 810 but should be very nice on 5X7. Does the Korona have a Packard?

 

[laz]

Does the Korona have a Packard?

The copy camera that the lens came from did. I should mount it on the board I put the lens in, correct?

An educated guess is it won't cover 810 but should be very nice on 5X7.

The camera came with both an 8x10 and 5x7 back so I guess this is the lens for the 5x7......

Thanks Jim!

-Bob

 

[jimgalli]

Bob, Copy cameras worked at different distances than we normally do with our subjects. When a 280mm is making a 1:1 reproduction the bellows is actually at 550+mm so your 280 @ infinity just became a 560mm. It would likely cover 11X14 at that distance. The angle of light just keeps making a bigger circle as the bellows increases. So it would probably be a great 8X10 lens for copying.

In my Kodak 2D I mounted the biggest packard I could squeeze between the bellows folds right up against the front of the camera. That way the packard travels with the camera and you can use the same packard with any number of barrel lenses that may come along. If you're using a shuttered lens, you simply open the packard up and the rear element of a modern shuttered lens rests inside the packard's open aperture.

 

[laz]

Bob, Copy cameras worked at different distances than we normally do with our subjects. When a 280mm is making a 1:1 reproduction the bellows is actually at 550+mm so your 280 @ infinity just became a 560mm. It would likely cover 11X14 at that distance. The angle of light just keeps making a bigger circle as the bellows increases. So it would probably be a great 8X10 lens for copying.

Ahhh I get it!

In my Kodak 2D I mounted the biggest packard I could squeeze between the bellows folds right up against the front of the camera. That way the packard travels with the camera and you can use the same packard with any number of barrel lenses that may come along. If you're using a shuttered lens, you simply open the packard up and the rear element of a modern shuttered lens rests inside the packard's open aperture.

Wow, thanks for that info, that saves a lot of trouble and opens up new possibilities for aquiring more lenses in barrel!

-Bob

 

[jimgalli]

....and opens up new possibilities for aquiring more lenses in barrel!-Bob

Crap. More competition.

 

[laz]

Crap. More competition.

Think positivly Jim. Better customer.