12x10 Dallmeyer 3D Rapid Portrait Lens

[jonw]

I just received a barrel lens which is 4 inches long by 2.5 inches wide with an aftermarket installed aperture that is marked f11 through f44. It is identified as a 12x10 Dallmeyer 3D f6.3 lens. I searched the Vade and the best description appears as though this may be a Dallmeyer Rapid Portrait Portrait lens which came in 6 sizes from 1/1 plate to 25x20. The Vade also indicates that lens design may contain thorium in the glass. The glass does appear to be a RR design. Does anyone have anymore insight, thoughts on how it may perform and/or other information of this lens? Your insightful responses are appreciated. Jon

 

[Ole]

Could it be a Dallmeyer Series D No. 3?

If so, my source has it in seven focal lengths - 230, 320, 430, 480, 610, 790 and 940mm - with max aperture "ca. F/6". It's listed there as a Petzval variation.

 

[jonw]

Ole, in looking closer at the barrel, it not only states on the barrel that is a
"3D" on the line below that it is inscribed "12x10 Patent f6.3". The name is JD Dallmeyer with SSN30678 London

Does this help shed more light? Thanks. Jon