View Full Version : Brass lens question

Tim M
01-23-2009, 01:32 AM
Hi gang,

I have a brass lens (no shutter) that I want to use for a wet plate camera that I am going to build.

It is 2" wide and 3" long at the flange and no other markings. What size plate will this cover? Will it cover an 8x10?


01-23-2009, 01:55 AM
That's impossible to tell without knowing what type of lens it is.
If it's a Petzval, it won't cover - the focal length would be about 3". If it's a WA Aplanat, it could cover 20x24".

Tim M
01-23-2009, 02:03 AM
Is there any way to figure out what type of lens it is?

01-23-2009, 02:12 AM
http://uk.youtube.com/watch?v=CIFNdfjem18 Watch this. It'll show you what the focal length and f/stop is at least.

Tim M
01-23-2009, 12:29 PM
Thanks guys. Appreciate it.

Ty G
01-23-2009, 01:32 PM
If it is an aplant or Rapid Rectilinear, then when you unscrew the rear and take the elements out. If they are two lenses glued together making one lens, then it is an RR/aplant/anastigamt. If the rear elements are two seperate glass with a washer or an air space between them, then it is petzval.. Take your lens and a big cardboard box. and open the front door to your house, stand inside in the darker area and hold the lens in front of the box and you will be able to determine how big the image circle is as well as the focal length.