ulf Posted April 12, 2021 Share Posted April 12, 2021 Last Update: 03 April 2021 agb/labelFinalized: Work in progress.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: NoLens type: Manual focus, Extreme tele lens, true long focal designDesign: Achromat, 2 elements in 1 groupFocal length: 400 mmAperture range: f/5.6 – f/32, Manual, 24 bladesSensor format/coverage: up to 24 mm x 36 mmMount: Wrayflex-thread adapted to M42 x 1 thread, at the end of the focussing bellowsHelicoid: No, Focussing with a bellow at the rear of the lensFlange Focus distance: M42/45.46 mm,Front filter: 75 mm x 0.75 mmIntroduction year: ca 1954S/N of test object: 40530 Image of test object:The top image in this post:https://www.ultravio...dpost__p__25241 Transmittance SummaryDefinitions of the parameters belowRange: The FERNOBJEKTIV 1:5,6 f=40cm transmits 1-90% in an increasing slope from 317nm to 400nm.TVISmax (%) = 97%T400nm (%) = 90%T365nm (%) = 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.λUV HMvis(nm) = 340nmλUV HM400(nm) = 337nmλUV Zero(nm) = 317nmThese 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 GraphsUV-NIR, Novoflex FERNOBJEKTIV 1:5,6 f=40cmThe 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=40cmUV-Log, Novoflex FERNOBJEKTIV 1:5,6 f=40cmNumerical Spectra Data available: Yes 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. 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.Image samples:See this and the following post:https://www.ultravio...dpost__p__25265 Link to comment
nfoto Posted April 15, 2021 Share Posted April 15, 2021 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 ... Link to comment
dabateman Posted April 15, 2021 Share Posted April 15, 2021 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. Link to comment
nfoto Posted April 16, 2021 Share Posted April 16, 2021 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. Link to comment
ulf Posted April 16, 2021 Author Share Posted April 16, 2021 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. Link to comment
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