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Thread: Jamin Darlot Convertible "Can Type" vs Cone Centralisateur

  1. #21

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    Re: Jamin Darlot Convertible "Can Type" vs Cone Centralisateur

    Quote from the book...According to Kingslake, it is a modified Petzval, since in the basic positon the design reoccurs with the separatable rear group. Fabre on the other hand, places it in the category of multiple focus lenses, together with Chevalier's Verres Combine's and Porro's Anallatic, pointing out its versatility. The versatility of the cone is also underscored by the inscription on the barrel "Paysage" and "portrait". Similar to the later lens "Objectif a foyer multiple et lentils additionelles di Derogy" from 1858, a divergent lens could be mounted at the center of the barrel on the appropriate threads. unquote.

    from: Photographic Lenses of the 1800's in France by Corrado D'Agostini.

    Looking at the Petzvals of Jamin in the book. He did make normal barrel Petzvals and I still maintain my Albion Albumenizing lens is a Jamin. It has been chromed methinks by a very enthusiastic collector.
    Last edited by andrewch59; 4-Oct-2015 at 20:09. Reason: typos

  2. #22

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    Re: Jamin Darlot Convertible "Can Type" vs Cone Centralisateur

    I have checked D'Agostini's book this morning.

    I quote -

    "By the mid 1860's, cones were made in different shapes. Menchini reports that Darlot also adopted the cylinderical form for the centralising cone after 1865."
    There is an example on page 133 with the "loose signature" engraving which was also used late in the Century, and with no serial number.

  3. #23

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    Re: Jamin Darlot Convertible "Can Type" vs Cone Centralisateur

    Hi Steven, I was particularly looking for paysage and portrait to link Alex's lens to Jamin/Darlot, does this engraving appear on other makers too?
    The last paragraph was a quip thrown in about my chrome lens, I have searched the web for months to find the quote that states that the quick acting cdv portrait lens sold by the Albion Albumenizing company Glasgow was in fact made by Jamin. Cannot find the quote to substantiate the claim.
    I have asked Corrado who cannot confirm. Its just a thorn in my side until I find that quote!
    Last edited by andrewch59; 5-Oct-2015 at 20:23. Reason: typo

  4. #24

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    Sep 2010
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    Portland, OR
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    Re: Jamin Darlot Convertible "Can Type" vs Cone Centralisateur

    Click image for larger version. 

Name:	titaniasmall copy.jpg 
Views:	71 
Size:	160.6 KB 
ID:	140714 Not sure if anyone is interested in the visual qualities of this lens, but here is a 7.25" by 9.25" wet plate I made with the 13 inch f4.5 can type lens in the Original Post. It looks French.

  5. #25

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    Re: Jamin Darlot Convertible "Can Type" vs Cone Centralisateur

    Here is a new one - very heavily disguised. Described by a frequent lister (who should know better, as he has listed early lenses as projection lenses a few times before!) as a "reverse Petzval design". Obvious a can version - minus the short sleeve and hood!

    Disregard the reported sale price!

    I have had this lens in my hands now. It is clearly marked Jamin Darlot on the the rear lens and traces on the front achromat (Very faint due to much rebalsaming!) say the same.
    There is no trace og paysage/portrait markings, the the barrel splits to reveal a mounting ring with an B mark. Which means there must have been a A ring! This ring B cannot support an extra lens. It is more like a base for mounting central stops for the Petzval function. The A ring might have been similar - but with a lens mounted. Or the A ring may have had the full barrel diameter and been a support for washer stops when the front part was used in Paysage mode. Darlot was still using black paper tape at this stage to blackout the mounted rack.
    Attached Thumbnails Attached Thumbnails image.jpg   image.jpg   image.jpeg  
    Last edited by Steven Tribe; 22-Feb-2018 at 06:28.

  6. #26

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    Re: Jamin Darlot Convertible "Can Type" vs Cone Centralisateur

    Will be adding some new info/photos during the next few hours - a lot to source but will just add on to this skeleton reply gradually. As this is most comprehensive thread on Jamin/Darlot innovations in the middle late 1850’s there is one other important relevant thread ... here.
    https://www.largeformatphotography.i...Petzval-Lenses.
    This includes,perhaps the best YouTube video from Eddie Gunks with a rare complete convertible.

    https://www.youtube.com/watch?v=tfFHw4mEkbs

    I have “read” the section in the Booklet on Jamin and Darlot a number of times. I feel that not everything is made clear, perhaps due to my very imperfect French! There were a lot of patents/registered designs made between 1854 and 1860 which apply to the Convertible model (splits into two distinct halves), the Cone model (originally also with convertible status and which continued as a “prestige” model well into the Darlot alone era. Finally, there was the “Can” version (described in French as the “Cylindrique” version) They appeared in the period 54/60 and it is likely that all 3 versions were available at the same time.

    Summing up the innovations (claims) were:

    1 Reduction of “divergent” light rays compared with normal Petzval constructions (only applied to the can and cone models).

    2 Reduction of aberrations through adjustment of the distance between the front and rear lens cell ( this applies to the non can/cone version as well).

    Then there is the question of the 3rd lens and the central stop system. Fortunately I have 3 examples of the of the same lens and size from 3 different periods /engravings - early Jamin, Jamin Darlot and an anon. version (UK market).

    The first figure shows the patent figures. The figure to the left shows the complete lens with the back looking like a usual Petzval. The front have contains the achromat and a extra simple meniscus (+,+) (called “C”) fixed at a distance in the front cell. The right hand figure shows how the front part can be pulled out and used as a landscape meniscus lens with lens “C” reducing the focal length.
    The crude diagrams were obviously made at a very early stage in connection with the patent application - the final production brass mounting design is very complex and provides central stops with screwed mounting.

    Eddie Gunks’ video shows the final mounting system developed by Jamin.

    Unfortunately, this convertible early Darlot, along with the later Universal, must be about the most the frequent lenses found in very incomplete state with no photographic use whatsoever!
    Attached Thumbnails Attached Thumbnails 31A1AD21-A325-413D-9B95-081DEAA320F3.jpg  
    Last edited by Steven Tribe; 1-Dec-2022 at 02:01. Reason: Orthographic

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