Which Petzvals have the Dallmeyer modification?

[DrTang]

Question:

I have a Briggs Special Portrait lens 5x8 f5 which is a rebranded something.. and similar to a Hyatt Special Portrait??

anyway..in reading thru the forums..it seems my lens might be assembled backwards...it has two separate elements up front with the soft focus markings 1 thru 4, and the bigger cemented element in the rear

is this backwards? and if so..how would one adjust the softness w/o taking the lens off the camera since those elements would be on the back inside the camera

also.. who the heck really made it?

pix:

https://www.flickr.com/gp/11191083@N00/oV6U6a

and

https://www.flickr.com/gp/11191083@N00/7wpB4B

[tjuliuxue]

hugo meyer atelier petzval from Germany is also modified petzval

[ndavidson27]

Adding to this thread, Ross made a "Universal" line of petzvals, which had the Dallmeyer designed flipped rear grouping. They seem to be quite scarce and I can't find any historical information on it. My example is 10" at f5.

[Steven Tribe]

It has been written in another thread, but deserves to be repeated here-

Ross's later Cabinet series adopted the Dallmeyer rear lens arrangement!

[Mark Sawyer]

My Ross No. 3 Cabinet Petzval (serial no. 56993, putting it 1890-95, according to Wilkinson and Glanfield) has the classical layout.

I've taken to classifying the two layouts by the shape of the rear positive lens. The illustration below, taken from Kingslake's History of the Photographic Lens, shows the Petzval element to be slightly bi-concave, while the Dallmeyer is slightly meniscus, (though both are close to plano-convex.) I'd be interested whether others think this is a reliable method, as I'm unsure whether the curves changed on either design through the years...

[Steven Tribe]

My Ross No. 3 Cabinet Petzval (serial no. 56993, putting it 1890-95, according to Wilkinson and Glanfield) has the classical layout.........

When I wrote "later Cabinet series", I meant sometime in the 20th Century! This is from the Professional Kodak Catalogue of 1934. Of course, sales of Portrait Petzvals were pretty low by then as the number of numbers of Studios were stable - or already falling. This would also explain why we see virtually none of the additional Dallmeyer Patent Petzval sizes that were offer in the same 1934 Catelogue.

[Steven Tribe]

Just to add another known convert to the Dallmeyer rear cell design in the 20th Century.

The late series 1a Petzval from Voigtæander also had it. This is the series that mostly had smaller sizes and managed F2.3

[Mark Sawyer]

Just to add another...

Interesting! Looks like they also reduced the diameter of the rear cell, which would of course be magnified by the front cell. Half-way between t5he Petzval Portrait and the Petzval View, (Orthoskop).

BTW, I just noticed the drawing above, taken from Kingslake's History of Photographic Lenses, refers to it as the Orthostigmat. An obvious mistake, as anastigmats didn't appear til nearly 50 years after the Orthoskop was designed.