Objective without signature, but lens has writings at the edge

[Ron (Netherlands)]

Just got this pillbox lens in the mail; not signed from the outside but nice as addition to my little collection of landscape lenses....
However when dismantling the lens, I found a complete signature at the edge of the lens, see below pictures, even with a year (of manufacture?):

[Steven Tribe]

Many Jamin and early Darlot lenses were delivered to camera makers, and perhaps also retailers, without brass engravings. Might have something to do with the Franco-German animosities . The 1869 date is perhaps a clue (Franco Prussian conflict of 1870/1872),

[ic-racer]

"Landscape" lens, so is that a cemented doublet? Is there some aperture mechanism in the snout?
Nice find!

[Ron (Netherlands)]

"Landscape" lens, so is that a cemented doublet? Is there some aperture mechanism in the snout?
Nice find!

Thanks, yes it is a cemented doublet, and yes it has in its 'snout' a ring that can hold the aperture disks, but the disks are gone (as is the brass cap):-(

These are from my Darlot pillbox lens which has a signed barrel, but they don't fit the lens that has no signature, just a little to big:



...the barrel from the lens with no signature looks very much like the ones made by Derogy, although Derogy of course also signed its barrels...

It is quite a heavy barrel. Just measured its focal length which is 300mm. The lensdiameter at the back is close to 55mm. The front opening without disks is 25,5mm which combined with the focal length stands for an f-stop of about f = 11,7.
The aperture disks should measure about 37mm in diameter.

The internal diameter of its mounting ring measures 74,25mm and - as the lensbarrel - has a (Continental) M1.0 threadpitch.

[Ron (Netherlands)]

The 1869 date is perhaps a clue (Franco Prussian conflict of 1870/1872),

at closer look the year reads 1864...

The complete edge writing is as follows: 33 1/2 78 A Darlot Rue Chapon 14 a Paris 1864

Anyone any clue on the first numerals?

[John Layton]

How cool is that...the signature and date on the edge of the element? And here I was, thinking that the phrase "an objective without signature" was possibly referring to a completely boring/sterile lens...one without a (an optical) signature!

Would be very curious, though, to get a sense of this particular lens' true (optical) signature!

[Steven Tribe]

Best guess for 33 is obvious focal length of 33cm. Millimeter is a more modern photograph convention!

There is no certain knowledge about who made the brass work for A.Darlot and Jamin. The only addresses we have for Darlot are in the very center of Paris which are hardly suitable for the kind of processes needed for metal work. Derogy had a more village location with access to a watermill, I seem to recall.

I enclose the list of the range of landscape meniscus lenses from Jamin/Darlot in the 1860’s. The apparent lack of a specific numbering system 1,2 etc(which came later) is probably due to these being made to suit a specific sliding box type camera.

Sorry about “Australian” type image-solution is beyond me to-day. This is another amateur photo extract from the Pont et Princelle booklet on Jamin and Darlot.

[Ron (Netherlands)]

Many thanks Steven, hope you don't mind I've put your image 'upside down'....



My Darlot signed pillbox lens has also edge writings, and read: aF 31 1/2 Darlot Paris 14

Maybe the name of the street has vanished although number 14 stands for the correct address.
And it is hard to see whether the 'aF' is correct, could also be something like aFl or just Fl.

Further the two lenses - signed and non-signed barrel - compared, one can say that the non-signed has finer inner threads and looks overall a little bit finer made - although the focussing knob of the signed Darlot barrel is more distinctive.

Looking at 'your' table, one can further establish that when "Ø" means the diameter of the glass, both lenses fit in the 4th row, however when the diameter of the barrel is meant, they would both fit in the 5th row.
By the way, that must be an enormous (heavy) pillbox lens, the one with a diameter of 16,5 cm!

Further the questions rises what in the table the object is of the 'Dimensions'... perhaps the size of the plate when using the lens for reproduction purposes?

[Philippe Grunchec]

Best guess for 33 is obvious focal length of 33cm. Millimeter is a more modern photograph convention!

There is no certain knowledge about who made the brass work for A.Darlot and Jamin. The only addresses we have for Darlot are in the very center of Paris which are hardly suitable for the kind of processes needed for metal work. Derogy had a more village location with access to a watermill, I seem to recall.

I enclose the list of the range of landscape meniscus lenses from Jamin/Darlot in the 1860’s. The apparent lack of a specific numbering system 1,2 etc(which came later) is probably due to these being made to suit a specific sliding box type camera.

Sorry about “Australian” type image-solution is beyond me to-day.

Would have been fair to mention Pont and Princelle's name...

[Steven Tribe]

I have posted a very large number of “intentionally bad photos” from the P et P with their permission and have mentioned them many times in many threads. I assume that their very distinct photo/tables are immediately recognizable by almost everyone reading this, rather specialized, thread. I have added the source of the table.

Unfortunately, the image has been added to a Flickr account, where a formal reference to the French A to Z would have been appropriate.