The Doppelverant is a simple yet versatile stereoscope for viewing glass and paper card stereoviews. The viewer can be used as a table-top or hand-held stereoscope and was designed by Moritz von Rohr of Carl Zeiss Jena[1][2]. There was also a model available for viewing “normal” images and this device was named Einzelverant[1].
The introduction of the Doppelverant is unknown, but a manual refers to the introduction of the Verant lenses in 1903 and 1904[1]. The device was equipped with two Verant Model B achromatic lenses, optimised for achromatic, anastigmatic and distortion-free images.
The viewer could be supplied with lenses with a focal length of 70mm or 90mm[1]. The lenses have blinders and can be focused via a slider on the back that allows the lens holder to be moved over the base plate. The distance between the lenses is adjustable by moving a slider bellow the base plate. The distance can be read via an index on the base plate. The eyepieces can be unscrewed and show that each lens system consists of two lenses.
Slide holders were available for different stereo formats. This model has a holder for 6x13cm glass stereoviews and includes a removable frosted glass to diffuse the light. It could be replaced by a black screen for viewing paper card stereoviews. The name Carl Zeiss Jena is visible on the left lens holder and the right holder shows Doppel Verant in graceful italics. The base plate contains the abbreviation DRP (Deutsche Reich Patent) and the device has no serial number. The viewer’s legs are collapsible.
The build quality is less than that of the robust Zeiss Verant and with this model Zeiss Jena probably aimed at the enthusiastic amateur.
References
- Der Doppelverant (product description, manual and price list), Carl Zeiss Jena
- Moritz von Rohr – via: en.wikipedia.org