View Full Version : Derogy Multifocal Wet Plate lens

Jon Wilson
2-Jul-2009, 12:46
Has anyone ever seen one or these or know anything about them? I found this Derogy on ebay. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360164507952

Thanks. Jon

Jon Wilson
2-Jul-2009, 19:22
I don't know if I have made the calculations correctly or not, but this appears to be a triple convertible. The 2 sets of cells together appear to have a focal length of 5 inch f2.8, front cell only focal length of 10 inches f5.7, and the rear cell a focal length of 14 inches f8. The cells have a diameter of 1.75 inches and front cell to rear cell length of about 3.1 inches.

Besides the lens, the bonus I discovered is that the Derogy flange will fit my 6 inch f3.4 Gasc Charconnet imported by Geo. Bryant & Company (Petzval).

I would appreciate it if those who more knowledgeable can confirm or correct my calculations as to this Derogy.

Thanks. Jon

2-Jul-2009, 20:50
Funny that you made this post. i was just thinking about how i sold one of these lenses adn i had wished i did not....just tonight i was thinking about it!

the best part of it is the lens you now have is the one i sold! i sold it to jotepper who in turn sold it to yanliz...i check the feed back and on march 9 yanliz bought it from tepper! right about the time tepper had it on e bay. small world eh?

i know that it can be used complete or as a landscape lens as well. if you notice the bayonet mount allows you to use the front element in the rear but not the other way around. the most interesting part is that the inside bayonet mount (seen in the 4th picture) is actually a mount for a diopter. so if you had the various diopters you could have several different focal lengths in one lens. now i am not sure that you can use the rear element alone, try it and get back with us.

it is a fairly rare lens. i am sorry to have sold it but i am happy to know you now own it. small world eh? enjoy it and please post some photos when you make them.


Jon Wilson
11-Jul-2009, 21:16
Thanks Eddie. I appreciate the information. I have done a little further research and confirmed it is only a convertible lens with the present lens, but if it had included 2 supplemental lens it originally came with, one concave and one convex achromatic lens, this this little quarter plate lens could change its configurations to 5 1/4, 7, 9, 11, and 17 inches. The lens was in fact designed by a French Optician, Derogy.

Maybe someone will chime in and advise how difficult it would be to have an optician make the missing supplemental lens for this baby, recommend someone who could make such supplementary lens, or better yet have the original supplemental lens laying around in a Moroccan leather pouch. :)

I posted a couple shots I took with this lens tonight with some Type 55 film. The scans of the prints show streaks, but that is from the fixing goop you coat the print with. http://photo.net/photodb/photo?photo_id=9467152

I have also attached the scans here too.

I have taken a couple of chromes with this lens too, but have not have a chance to scan them.