View Full Version : Looking for info on my Gasc and Charconnet lens

Tony Kearney
8-May-2015, 16:54

I'm new to the forum so please forgive me if I'm asking the obvious. A few years ago I bought a brass lens from a camera store, they had no idea what it was and so I bought it for a good price, because I liked the look of it and wanted some lenses to play with wet plate photography which I was just getting into. Anyway somehow I worked out that it was a Gasc and Charconnet lens. It didn't come with waterhouse stops so now I'm wondering how I should determine it's f-stop value (without the Waterhouse stops) as, in the short term, I'll be happy to use it fully open with 4x5 film anyway. I know I'm sounding like a complete novice but any help would be appreciated.


8-May-2015, 18:48
French made.
Founded in 1860, finished in 1890.
"Portrait lens patent" means that the lens was exported to the US or English market.
"Quick Acting" means larger aperture for children and portrait shootings.
Congratulations, Tony.
It's a good Petzval lens.

8-May-2015, 18:49
These are nice, fast lenses. I have two, and keep them. It should be about F3.6. You can tell by holding it about 5 inches from a wall opposite a window. Point it towards that window while moving it in and out away from the wall. Get a tree or kangaroo in the yard to focus on the wall. Measure from the wall to the waterhouse slot. That's the focal length. Now hold the lens up to the window, looking into the FRONT. Hold your ruler to the front and measure the apparent circle of light you can see. That's the entrance pupil. Now divide focal length by entrance pupil for the lens speed.

Tony Kearney
9-May-2015, 05:03
I worked out that the focal length is 165mm (water house stop slot to focussed infinity on wall) and the apparent circle 45mm so 3.6 is about spot on. I've mounted it on a modified speed graphic lens board and taken a few images which I'll process in the morning. Looking forward to seeing the results.

9-May-2015, 08:13
I figured it was about a 6", and the Quick Acting ones are around F3.6. When you handle as many lenses as I have, you get to where you can tell just looking at them.

Here is one of mine, 2nd from the left, along with some other French lenses (L-R Darlot, Gasc Charconnet, Hermagis, Jamin).


Tony Kearney
9-May-2015, 18:34
An image taken yesterday with the lens133626

Steven Tribe
10-May-2015, 13:08
G & C ended in 1887 and became Clement & Gilmer - in 1890, when Laverne provided capital, the C & G was continued with many variations of the names!
You have a fairly late one, there is a serial number 31284 shown in Corrado's book.

I have always considered the decorative engraving the absolute winner in the ugly category! Well distinctive, anyway!
It was fairly standard on the late, english language, export lenses, but appeared as early as serial number 7919 on more traditional "french" versions.

There are plenty of earlier threads here you will find interesting - look at the bottom of this page - with plenty of tjeories about the engraving and images of similar lenses to ypurs.

Tony Kearney
13-May-2015, 05:12
thanks steven

Tony Kearney
13-May-2015, 05:13
there are some beautiful pieces of brass and glass there Goamules, can't imagine the qualities and quirks of the images that come from each idiosyncratic lens

13-May-2015, 05:43
This 8x10 was taken what a larger 14" Gasc & Charconnet I have. It's a favorite.


Tony Kearney
13-May-2015, 17:05
beautiful, was that stopped down at all or fully open? Mine didn't come with any water house stops so I'm going to make up a few just so that I can use it in brighter light conditions

15-May-2015, 08:16
It was wide open, natural light under a skylight. I used a packard shutter, probably around 1/10th of a second.