mike_netecke Posted February 5, 2003 Share Posted February 5, 2003 I have a circa 1880s Dallmeyer RR that has an orignal waterhouse stop with it stamped f22 that is 5/8" in diameter. That would suggest a focal lenght of 11 3/4". However the lens focuses at infinity at about 25". The lens has the name, patent info and "25x21" stamped on it. The lens is mounted on an vintage 18x22" camera and has plenty of coverage for it. It is all brass, about 8" long by 4" in diameter and in almost perfect condition. Anyone have any information on the lens, type or FL?? Did they use the US system then? If so how would I calculate the proper stops. Link to comment Share on other sites More sharing options...
colin carron Posted February 6, 2003 Share Posted February 6, 2003 Mike, Is it possible your waterhouse stop comes from a different lens? Standard Dallmeyer RR lenses were usually f8, the Dallmeyer Wide Angle Rectilinear was f16 and the Rectilinear Landscape was f14. For the RR the normal coverage for 25in was 18x16. (All according to the Vademecum). I have a nice Ross RR (extra fast) of about the same age as yours which is about f5.6 and is calibrated in US stops (Universal Standard?) as US 2. US stops afaik were based upon the fact that the fastest lens at the time (Petzval Portrait) was f4.0. So US 1 = f4.0, US 2 = f5.6 etc. Link to comment Share on other sites More sharing options...
c_p_goerz Posted February 6, 2003 Share Posted February 6, 2003 Are there two cells in this lenses construction? CP Goerz Link to comment Share on other sites More sharing options...
mike_netecke Posted February 7, 2003 Author Share Posted February 7, 2003 I checked the lens and found the focus at 10 feet to be about 45". There are two cemented elements, one to each end. It's dark and snowing so I can't get an infinity focus yet. I posted some pictures here: http://www.photo.net/photodb/presentation?presentation_id=188753 In the gallery under; Dallmeyer RR 25x21 Link to comment Share on other sites More sharing options...
ian_leeden Posted February 7, 2003 Share Posted February 7, 2003 hello mike, re your dallmeyer lens..... the following is from a dallmeyer ad in a 1914 copy of the british journal of photography " this is the original R.R.patented by J.H. Dallmeyer in 1866, it remains an excellent lens for many purposes. The larger sizes in particular are recommended for open air groups." the largest size listed is the #12 ...at 25x21.... 4inch dia lens... focal length 33 inches... max aperture f8 ....... price 31pounds and ten shillings Link to comment Share on other sites More sharing options...
struan_gray Posted February 7, 2003 Share Posted February 7, 2003 The stop size is the size of the hole as seen through the front of the lens when the stop is in its slot. The front and rear elements of a RR are both positive lenses, so they will magnify the hole in your Waterhouse plate. The easiest way to check is either to meter off the ground glass and compare against another lens with a known f-number, or to do test exposures until middle grey comes out middle grey. I love the size of that thing. Kids will *not* misbehave in front of your camera :-) Link to comment Share on other sites More sharing options...
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