Novoflex 40cm f/5.6 Fernobjektiv

[ulf]

Last Update: 03 April 2021 agb/label

Finalized: Work in progress.

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Novoflex 40cm f/5.6 Fernobjektiv

 

Manufacturer: Novoflex. The achromat was computed and produced by Staeble Optik in Schongau.

Lens Label: ( NOVOFLEX ) FERNOBJEKTIV 1:5,6 f=40cm <P serial number>

Currently manufactured: No

Lens type: Manual focus, Extreme tele lens, true long focal design

Design: Achromat, 2 elements in 1 group

Focal length: 400 mm

Aperture range: f/5.6 – f/32, Manual, 24 blades

Sensor format/coverage: up to 24 mm x 36 mm

Mount: Wrayflex-thread adapted to M42 x 1 thread, at the end of the focussing bellows

Helicoid: No, Focussing with a bellow at the rear of the lens

Flange Focus distance: M42/45.46 mm,

Front filter: 75 mm x 0.75 mm

Introduction year: ca 1954

S/N of test object: 40530

 

Image of test object:

The top image in this post:

https://www.ultravio...dpost__p__25241

 

Transmittance Summary

Definitions of the parameters below

• Range: The FERNOBJEKTIV 1:5,6 f=40cm transmits 1-90% in an increasing slope from 317nm to 400nm.
  
• T_VISmax (%) = 97%
  
• T_400nm (%) = 90%
  
• T_365nm (%) = 82%
  This high percentage is an indicator for quite short exposure time under typical UV-pass filtration peaking around 360 nm or when using 365 nm UV-LED illumination.
  
• λ_{UV HMvis}(nm) = 340nm
  
• λ_{UV HM400}(nm) = 337nm
  
• λ_{UV Zero}(nm) = 317nm
  
• These three values indicate that the lens is working even for some upper UV-B photography with some filters and a few for this, suitable cameras.
  

Spectral Transmission Graphs

UV-NIR, Novoflex FERNOBJEKTIV 1:5,6 f=40cm

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

 

UV, Novoflex FERNOBJEKTIV 1:5,6 f=40cm

UV-Log, Novoflex FERNOBJEKTIV 1:5,6 f=40cm

Numerical Spectra Data available: Yes

 

 

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Filters and how to use them on this lens:

The front filter thread is an unusual 75 mm standard filter thread.

 

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.

 

An alternative, is to putty-mount a filter directly inside the lens. There are several flat surfaces that likely would work to mount a filter or a step ring fitting the filter.

 

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Handling and focussing:

Difficult due to the long focal length.

A stable tripod, or two, are needed to support the lens.

 

Flare and sun-stars:

TBD

 

Sharpness:

High for the age of the lens.

 

Lens distortion:

TBD

 

Chromatic Aberration in UV:

Yes both axial and lateral. Improves by stopping down and can often be tolerable.

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Image samples:

See this and the following post:

https://www.ultravio...dpost__p__25265

[nfoto]

My 40cm Novoflex 'Fernobjektiv' set up and ready to be deployed .... I could never get anything remotely stable using the Pistol Grip section, so set the system up using alternate parts I already had at my disposal. The PN-11 extension ring at the end of the PB-4 bellows gives a better near limit and one avoids extending the bellows device to its full extent. As the front head of the Novoflex ends in 48mm threads, it was a breeze to incorporate a Baader U filter at its rear end, and link together the lens and the required F mount for the bellows unit. The CPU at the very end allows full EXIF data to be recorded. Admittedly a little bit of extravagance but we deserve pandering to ourselves in these bleak times.

 

 

In field tests, the 40cm lens head compared favourably in terms of required exposure to the UV-Nikkor. For sharpness the UV-Nikkor wins hands down, which is no big surprise. However the UV-Nikkor despite its manifold attractions is no 400mm ...

[dabateman]

Birna, compare your UV Nikkor on the AIS teleconverter with one of your m43rds cameras. That should be similar in field of view, and might be sharper depending on your 2x TC. But I think you said it was ok.

[nfoto]

A 2X TC robs two stops of light. So with the UV-Nikkor already f/4.5, your new starting point is f/9 and a need for stopping down more to get the better result. it is true the Novoflex also improves upon stopping down, but there is the f/5.6 option at hand. Besides, I'm interested in 400 mm not the "equivalence". My Panasonics are OK for UV video, but for stills I much prefer the Nikons.

 

I have a Piesker 400mm f/4.5 that might be a direct competitor to the Novoflex, so a shoot-out between them is on my to-do list. First, I have to attend to the annual tax returns though.

[ulf]

If anyone else wants to try out this old lens head, there is an interesting lens for sale here:

https://www.ebay.com...y-/202952142750

 

I think this lens tube version has an internal focussing worm mechanism, but I have not tried this model.

The camera mount is also a bit strange, but could likely be changed to something fitting. At this price it would be OK to glue whatever is needed in the camera end, as a small DIY-project.

Depending of age the lens head might not be interchangeable with slightly more modern heads.

 

IMHO, The T-Noflexar is the best of the 400mm-lenses, even if the transmission is slightly lower and the UV-reach is not that deep.

The T-Noflexar has an UV-reach similar to the 35mm Noflexar lens. That is quite enough for outdoor UV-photography.