View Full Version : Aperture of Rapid Aplanat No2

17-Nov-2009, 01:02
I have a brass lens marked Rapid Aplanat No.2 in script on the side of the barrel. The only other marking is a 7 point small star on the mounting ring...

It appears to be around a 200mm lens...it has a slot for Waterhouse stops (but I don't have any for it)...

Would anyone know what I could approximate the aperture of this lens to be (wide open)?

Any help would be much appreciated...


Steven Tribe
17-Nov-2009, 01:53
The no. 2 designation and 200mm go very well together. French and German makers used the code no. 1 : 9x12cm, no. 2 : 13/18cm etc. An aplanat/RR of around 200mm would be OK for 5x7". I can say without fear of making a mistake that the aperture will be between modern F7.7 and F8.0!! If they were faster (under F7) then the maker would have advertised it in the engraving (Super rapid, extra rapid etc.)! Marks on mounting flanges can be a problem as they were very often subcontracted to other workshops who could turn brass. Only people like TTH, Steinheil and Busch have reliable info on their flanges. ICA (Germany) used a star on their products (pre 1925).

17-Nov-2009, 05:21
As Steven has said, very likely to be f/8. See here for a Busch ad with Rapid Aplanat specs:



17-Nov-2009, 08:53
Thanks for the quick replies...

That's exactly what I needed to know...

Thanks again,

Louis Pacilla
17-Nov-2009, 18:41
Hi DanK

I have a #4 Busch's Portrait Aplanat 14" f6 w/ marking's including the 7 point star w/ an "R" in the center of the star( I would guess for the location Rathenow).
I also have an #5 Emil Busch Rapid Aplanat 18"f8 w/ the same mark on the flange. Finally I have a Smedley & Co Blackburn England #5 18"rapid aplanat. This is a Re-branded Emil Busch #5 Rapid aplanat 18"f8 identical in every way including the star w/ the R on the flange.
So I believe your lens is an Emil. One of the best Aplanat's out there.Very sharp.

Louis P.

17-Nov-2009, 20:01

Thanks for the information....that's very good to hear...

I looked closer, and there is an 'R' in the center of the star....

Thanks again,