Steven Tribe
30-Mar-2020, 03:18
I think I must be one of, perhaps, three people who still bid for Petzvals in auctions!
This one was described as being French , perhaps because it was listed after a smaller Hermagis Petzval.
It arrived this morning - and it certainly isn’t French.
The appearance/color of the brass suggests it is not a brass alloy I am used to seeing.
The surface of the lens barrel shows lot of micro- striations that would have been smoothed out in a French
lens (I have see most manufacturers).
The lens is pre Waterhouse slot design as the slot/support rings/sleeve cut are well made - but are clearly a early “modernization”.
The achromat has been mounted in a lathe. This was common in the UK (unfortunately!) perhaps because this is how achromats were mounted in telescopes, whilst French lenses were always (God bless them!) screwed in.
The edges of the lens faces (perhaps 2/3mm) - beyond the optical path - had been ground. This is something I have never see in a Petzval construction, but only after the introduction of new designs in the 1890’s.
The focussing drive has been modified, both on the sleeve and the barrel. There are a pair of (unused now) central screw holes in the sleeve under the present tangential as well as the usual group of 4. The barrel has had a new wide section with a track soldered in. Splendid metalwork!
This one was described as being French , perhaps because it was listed after a smaller Hermagis Petzval.
It arrived this morning - and it certainly isn’t French.
The appearance/color of the brass suggests it is not a brass alloy I am used to seeing.
The surface of the lens barrel shows lot of micro- striations that would have been smoothed out in a French
lens (I have see most manufacturers).
The lens is pre Waterhouse slot design as the slot/support rings/sleeve cut are well made - but are clearly a early “modernization”.
The achromat has been mounted in a lathe. This was common in the UK (unfortunately!) perhaps because this is how achromats were mounted in telescopes, whilst French lenses were always (God bless them!) screwed in.
The edges of the lens faces (perhaps 2/3mm) - beyond the optical path - had been ground. This is something I have never see in a Petzval construction, but only after the introduction of new designs in the 1890’s.
The focussing drive has been modified, both on the sleeve and the barrel. There are a pair of (unused now) central screw holes in the sleeve under the present tangential as well as the usual group of 4. The barrel has had a new wide section with a track soldered in. Splendid metalwork!