Very Fast Rare Brass Petzval Lens By Ross, London C. 1870. Wet Plate & Dags.
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Very Fast Rare Brass Petzval Lens By Ross, London C. 1870. Wet Plate & Dags.:
Around 1870 Ross London made a small number of very fast Petzval design Portrait lenses. This one is marked for CDV. It will actually cover up to whole plate, (8.5" x 6.5"), though here will exhibit extreme example of what some term "Swirly Bokeh". Otherwise, using it for 5x4 or even 7x5 should give a more conventional image quality, still with some swirl, or falling off of sharpness in the 7x5..
It is large, and heavy because there is a lot of glass. It weighs 2.3 kgs, (about 5 lbs). This is including the retaining ring and 1 waterhouse stop.
I measured the focal length at about 23 cms, about 9 inches. The maximum aperture looks to be F 2.7.
The glass is excellent and has no haze, fungus or seperation.
The rack and pinion focusing works well, being on the stiff side, which of course could be seen as a virtue as once focusing has been set, it should not move out of focus.
The brass has been stripped, and I think you can see this quite well in the photographs.
If you are considering trying either Wet Plate or Daguerreotype photography, the speed of this lens would be a great help.
The one (non original) Waterhouse stop gives an aperture of about F 4. It would be simple to make further Stops by using this as a template out of thin black card. There is also a burgandy coloured leather lens cap.
Shipping has to be by International Air Courier, which should take a few days, sometimes overnight, and be trackable door to door.
If you want to know how much this will cost to yur address, please email me. Generally speaking it should be around 45 GBPs internationally, but some countries may be more.
On 30-Mar-13 at 13:09:02 GMT, seller added the following information:
Correctio. The diameter of the retaining ring is 14.1 cms or 5-1/2 inches.NOT 5 inches.