Another Petzval lens question to the experts

[seven]

Since we're in radial drive mode lately, i would like to ask about your ideas of manufacturer of another lens :





FL is 360mm, about F4.5, no inscription whatsoever.


Thanks !

[Two23]

Did you take it apart and look at the edges of the glass? It's slotted, suggesting it was made for photography. Also has a brass lens cap rather than leather. If I remember right, most radial drives were American but the French made a few in the 1860s as well.


Kent in SD

[Jim C.]

It also has a awful lot of what looks like lathe marks on it too, if there was any engraving
whom ever did those marks probably took it all off.

[Steven Tribe]

Yes, but I think turning in a lathe with the large Waterhouse cut-out might be difficult?

This might suggest that an unwanted engraving " 20" EQF Projection Smiths NJ" has been removed, then the WH cut-out made?

Or, there was an engraving on a pre 1857 lens and this was on the brass square which was removed in connection with modernisation. This is not uncommon. There are lots of lenses where small section of engravings remain and some where the cut out section has been riveted onto another area of the lens.

[seven]

@Two23 - yes, no inscription on the lenses
@Steven - the WH cut-out looks like a later addition, so it is possible that the engraving was lost this way.

Found the letters "VI" scratched in two places - inside of upper side of barrel and under the flange. Not very useful information since it is scratched in by hand.
btw - the lens is quite large - 23cm high, 12cm diameter of shade, lenses diameter 9cm
Has anyone seen another lens that looks alike and with a known manufacturer ?

[Steven Tribe]

The VI mark is a typical thread marking during batch production. Threads were still being made by hands, so the best fits were marked as pairs for easy assembly at the end of the process. Look for matching roman numerals on the lens cells. Remember brass and glass work were done in separate locations! So at least 5 others were made at the same time. This suggests both an early "skilled" maker, but also one of the succesful, as the market for this size was not large and 6 is quite an amount.

It looks like a French (Paris) lens. There was at least 1 UK maker (Edinburgh) who made radial drive, but only in very small numbers. Most French lens edges were marked, but servicing does lead to removal through solvent use. I can't find an exact match to your brass design, but the radial drive from Francais in the 1860's is a very very close match - just the wheel knob on yours is the older (and more elegant!) double rim design. So Francais was perhaps using your lens as a template!

For some unknown reason, a number of well known makers also marketed lens in non-engraved version. I have a large Derogy landscape meniscus which is exactly a match of the normal Derogy style but which is only identifiable because of the edge ink marks.

[seven]

Thank you Steven !
Both VI marks are on the lens barrel, no marks on flange or cells (yes, perhaps the markings on the lenses were removed by solvent use at some point).
I think the reason for unmarked lenses from the old big manufacturers was early OEM business, they sold them bulk and the dealer engraved his brand, there are lots of examples for this.

[seven]

I think we have a winner Thanks again, Steven !
E Francais is a pretty close match. Found this (from a fellow member here) - http://www.apug.org/forums/forum379/...zval-lens.html - it's a bigger version, but with the double rim on radial drive and with engraving on the side of WH cut-out. So my lens i either unmarked or some previous owner did a very bad 'cleaning' job.

[Steven Tribe]

The APUG is almost exactly the same as the one illustrated in Corrado's book - just the focussing wheel with double rim. They both are "double enders" - with threads at both ends that fit the flange. So it could be easily changed into a long focus achromat using the front lens alone and reversed.

I think it is a Francais made lens.

[Jim C.]

Yes, but I think turning in a lathe with the large Waterhouse cut-out might be difficult?

Not really, if it's set up right very light cuts on a lathe work fine.