Looking for info on petzval lens

[Jim Cole]

I just acquired this new petzval lens and its markings show A.T. Thompson & Co Importers. Focal length looks to be about 6 1/4 inches (although I'm a little unsure how to measure it with the focus capability). The seller said that it may have been produced by Darlot, Paris for Thompson. I'm looking for a little historical perspective. The lens is about 5" tall and about 2 7/8 " across the lens shade.

Information is pretty sparse.

Anyone have any info they would like to share to help place the lens in time and place?





Thanks,
Jim

[Carioca]

If possible, you could try to carefully disassemble the rear glass elements from their housing. Some manufacturers wrote their brand and/or name on the side (rim) of the glass with a pencil.

[Jim Cole]

If possible, you could try to carefully disassemble the rear glass elements from their housing. Some manufacturers wrote their brand and/or name on the side (rim) of the glass with a pencil.

Thanks for that tip. I'll check it out if I don't get any other info.

[CCHarrison]

Its most certainly a magic lantern lens. A.T. Thompson & Co was known for their magic lanterns - and I dont believe they marketed camera lenses. Having said that it could be a Darlot made lens since they made both camera and lantern lenses...

Dan

[Jim Cole]

Dan,

Thanks for that piece of info. It does have only one focus knob like the Magic Lanterns. It would seem a camera lens would have dual knobs.

I'll keep fishing.

Thanks

[Jim Cole]

If possible, you could try to carefully disassemble the rear glass elements from their housing. Some manufacturers wrote their brand and/or name on the side (rim) of the glass with a pencil.

I tried disassembling the lens cells to check for pencil marks as suggested by Carioca. Alas, I couldn't get the front cell apart (I wanted to look anyway), and the only marking on the rear cell elements was a penciled number "12" on the edge of the thicker of the two elements. No sign of a manufacturer.

Thanks

[Gene McCluney]

Dan,

Thanks for that piece of info. It does have only one focus knob like the Magic Lanterns. It would seem a camera lens would have dual knobs.

I'll keep fishing.

Thanks

You are incorrect, camera lenses of this period also have just one focusing knob. But..camera lenses have provision for waterhouse stops, and your lens does not, which is a sure giveaway for it being a Magic Lantern lens. Now magic lantern lenses and camera lenses are the same in optical construction if a Petsval design, except for the slot for waterhouse stops.

a 12" lens is about right for a focal length for a magic lantern, as the magic lantern slides which are approx. 3x4" would just use the central "sharp" area of a 12" Petsval.

[Jim Cole]

You are incorrect, camera lenses of this period also have just one focusing knob. But..camera lenses have provision for waterhouse stops, and your lens does not, which is a sure giveaway for it being a Magic Lantern lens. Now magic lantern lenses and camera lenses are the same in optical construction if a Petsval design, except for the slot for waterhouse stops.

a 12" lens is about right for a focal length for a magic lantern, as the magic lantern slides which are approx. 3x4" would just use the central "sharp" area of a 12" Petsval.

Gene,

Thanks for the correction. Being new to these old lenses I did not know that the waterhouse stop slot marked the difference. I wasn't sure if it was a developmental time line or a camera/lantern difference that designated the waterhouse stops.

Focal length is about half of the suggested 12". If I project a sharp image on a piece of mat board, the focal length is about 6 1/2" as measured from the center of the lens, which is where I assume I should start the measurement with a dual group lens. I haven't had a chance to make a lens board yet to put this on my 4x5.

Thanks again

[Jim Galli]

I've seen many of these come and go. I do believe it probably is made by Darlot. A T Thompson was only one of many mfrs for the magic lanterns and some of the others actually say Darlot on the lens. Family resemblance is identical. It really doesn't matter much in any case. If you like the signature that a Petzval lens gives it matters little whose name is on it. Usually if you look real close on the focus knob you can find a tiny Made in France. Typically there are lots of 6" and a few less 8" that share that body. There were 10" ones but they are a magnitude larger. You should have some fun with it on a 4X5.

[Jim Cole]

I've seen many of these come and go. I do believe it probably is made by Darlot. A T Thompson was only one of many mfrs for the magic lanterns and some of the others actually say Darlot on the lens. Family resemblance is identical. It really doesn't matter much in any case. If you like the signature that a Petzval lens gives it matters little whose name is on it. Usually if you look real close on the focus knob you can find a tiny Made in France. Typically there are lots of 6" and a few less 8" that share that body. There were 10" ones but they are a magnitude larger.

Jim, Thanks for the additional info.

You should have some fun with it on a 4X5.

Looking forward to it. Your work has inspired me.

Thanks,
Jim