[Leica] Need HELP with ID of LF lens

[douglas.sharp at gmx.de (Douglas Sharp)]

Sounds like something from a optical laboratory set up, possibly for 
diffraction work,.
The exact EFL (Effective Focal Length) and BF (Back Focus???) to 3 
decimal places seems to support this. Looks like someone would be using 
it for measuring things in terms of wavelengths of light.
Douglas

Mark Kronquist wrote:

>Howdy found an interesting old lens or three yesterday
>
>The most interesting is a no-name barrel lens in a nice leather covered wood
>box 
>
>Lens has 7 inch EF scratched into the black along with BF 122.8 mm
>
>an index mark etched 7.063 inches
>
>a typed aperature scal from f2.5 to f16
>
>perhaps 20 iris blades
>
>A card marked EFL 208.28mm
>
>BF 191.515 mm
>
>resolution 176 lines per mm
>
>low contrast
>
>Is this a process camera lens (it does not look like one)
>
>A ex-military one (it is coated)
>
>It is much too well made for a hash-up (unless the hasher had a machine
>shop)
>
>176 lp/mm seems sky high for a LF lens, it is?
>
>Any idea of the value?
>
>Thanks
>
>
>mak@teleport.com
>
>
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