Antique THE LONDON STEREOSCOPIC CO LTD Quick Setting Portrait Lens no.3B 8413 " Optimus " ~~~ ENGRAVED TO BARREL thus ( THE LONDON STEREOSCOPIC CO LTD Quick Setting Portrait Lens no.3B 8413 " Optimus " ) ~~~ Early brass Lens approx 9 inches tall , with lens Diameters of approx 3.75 and 5 inches ~~ Original leather faced Lens cover to one end ~~~ Both lenses appear in VGC ~~~ Not my area of expertise so plenty of photographs and questions welcome ~~~
The London Stereoscopic Co. Ltd. Quick Setting Portrait Lens No. 3B is a rare, historically significant Victorian-era brass photographic lens manufactured in the mid-to-late 19th century.
This lens follows the legendary Petzval design optical formula, which was highly prized for portraiture due to its exceptionally fast maximum aperture (typically f/3). It provides razor-sharp clarity in the center of the frame and drops off into a dreamy, shallow depth-of-field with a distinct "swirly" background bokeh.
Key Characteristics & Background
- The Retailer / Manufacturer: The London Stereoscopic Company (later Ltd., founded in 1854) was one of the largest photographic giants of the 19th century. While they manufactured cameras, they also frequently commissioned or rebranded top-tier optical designs from master English lens makers—most notably J.H. Dallmeyer, whose own "3B Quick Acting / Patent Portrait" lens is considered one of the holy grails of early photography.
- "Quick Setting" (or Quick Acting): This designation means the lens was designed with an exceptionally wide aperture to gather maximum light. In the era of slow wet-plate collodion and early dry-plate photography, a fast lens was critical to reduce exposure times down to a few seconds so human subjects could sit still without blurring.
- The "3B" Designation: In Victorian naming conventions, the number and letter specified the physical size, focal length, and coverage. A 3B lens typically features a focal length around 290mm (roughly 11–12 inches). It was engineered to cover large-format plates like 5×7 or 8×10 inch views.
- Mechanics: It features a heavy, solid brass barrel and typically utilizes a rack-and-pinion focusing knob (the "quick setting" mechanism) along with a slot to drop in Waterhouse stops (interchangeable brass plates with holes) to alter the aperture.