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[UlfW]

Finalized: Work in progress.
Last Update:
Note: Additional information or links about this lens are welcomed and will be incorporated into the first post as time permits.

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Leitz 60mm Focotar f/4.5

Manufacturer:Schneider Kreuznach for Leitz Wetzlar, Germany
Manufacturer's lens designation: FOCOTAR 1:4.5 / 60 - LEITZ WETZLAR
Currently manufactured: No
Lens type: Enlarger lens for film up to TBD
Design: TBD
Focal length: 60mm
Aperture range: f/4.5 – f/22, Manual, 8 blades
Format coverage: TBD
Recommended magnification range*: TBD
Optimal magnification*: TBD
^{*Definitions reversed from normal enlarger definition, referring to the motif not the negative-plane}
Mount: M39 x 26tpi thread
Reverse mount: None.
Helicoid: No
Flange focus distance: TBD
Front filter: Only by special filter adapter. See below
Introduction year: 1956
S/N of test object: 2369056
Manufacturing year: 1969
https://www.l-camera...r_1:4.5_/_60_mm

Lens review (VIS), on the web:
Lens Manual on the web:

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Transmittance Summary
Definitions of the parameters below

• Range: The Focotar 60mm f/4.5lens transmits 1-73% in an increasing slope from 309nm to 400nm.
  
• T_VISmax (%) = 85%
  
• T_400nm (%) = 73%
  
• T_365nm (%) = 63%
  This low percentage is an indicator for long exposure time under typical UV-pass filtration peaking around 360 nm or when using 365 nm UV-LED illumination.
  
• λ_{UV HMvis}(nm) = 342nm
  
• λ_{UV HM400} (nm) = 337nm
  
• λ_{UV Zero} (nm) = 309nm
  
• These three values indicate that the lens is working for som UV-B photography with suitable filters and a few for this, suitable cameras.

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Image of test object:

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Spectral Transmission Graphs
UV-NIR, Focotar 60mm f/4.5

The transmission measurement accuracy into the end of NIR range is less good due to limitations in the light source.

UV, Focotar 60mm f/4.5

UV-Log, Focotar 60mm f/4.5

Numerical Spectra Data available: Yes

General comments about the UV-reach:
tba

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Filters and how to use them on this lens:
This lens has no front filter thread.
For front mounted filters a step ring of suitable dimensions has to be glued or temporarily putty-mounted onto the aperture adjustment ring that is the frontmost part of the lens

It is also possible to use rear mounted filters, either in lens mount adapters for mirrorless cameras like Sony A-series etc, or placed directly in the camera.

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Handling and focussing:
This Focotar 60mm f/4.5 must be used with a helicoid or macro bellows to set desired magnification.
On mirrorless cameras the lens's FFD permits focus to infinity with careful sizing of the helicoid or bellows.
However these lenses are designed and optimised for short focus distances. At infinity the result will not be optimal.

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Image samples:

Edited by UlfW, 21 February 2021 - 14:42.