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Nikon 80mm f/5.6 EL-Nikkor: old metal version

Lens
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#1 UlfW

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Posted 03 January 2021 - 12:54

Finalized: Work in progress.
Last Update:


Nikon 80mm f/5.6 EL-Nikkor:. old metal version


Manufacturer: Nikon
Manufacturer's lens designation: EL-NIKKOR 80mm f/5.6
Currently manufactured: No
Lens type: Enlarger lens for film up to 56mm x 72mm ( Ø100mm )
Focal length: 80mm
Aperture range: f/5.6 – f/45, Manual, 8 blades
Design: 6 elements in 4 groups
Flange Focus distance: 70mm
Recommended magnification range*: 0.067x – 0.5x.
Optimal magnification *: 0.2x
Mount: M39 x 26tpi thread + hidden 32.5 x 0.5mm thread behind a built in step ring.
Sensor format/coverage: up to 56mm x 72mm ( Ø100mm ) at 0.2 x magnification
Front filter: 34.5 mm x 0.5 mm
Introduction year: pre 1960?
S/N of test object: 933700
* Definitions reversed from normal enlarger definition, referring to the motif not the negative-plane

Lens review (VIS), on the web:
Lens Manual on the web: http://www.savazzi.n...El-Nikkor_2.pdf


Image of test object:

Unfortunately the lens is buried and hidden by my DIY focussing and aperture-control build. It was too difficult to disassemble for any photos.
Except for the text on the front ring this lens looks almost identical to the older EL-NIKKOR 80mm f/5.6 Nippon Kogaku Japan presented here:
https://www.ultravio...pan/#entry41477


Transmittance Summary

Definitions of the parameters below
  • Range: The El-Nikkor Old Metal lens transmits 0-70% in an increasing slope from 310 nm to 400nm.
  • TVISmax(%) = 73%
  • T400nm(%) = 70%
  • T365nm(%) = 60%
    This high percentage is an indicator for relatively short exposure time under typical UV-pass filtration peaking around 365 nm.
  • λUV HMvis(nm) = 341nm
  • λUV HM400(nm) = 340nm
  • λUV Zero(nm) = 311nm
  • 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, EL-NIKKOR 80mm f/5.6, old metal version
Attached Image: EL-NIKKOR 80 Old Metal Full.png
The transmission measurement accuracy into the end of NIR range is less good due to limitations in the light source.

UV, EL-NIKKOR 80mm f/5.6, old metal version
Attached Image: EL-NIKKOR 80 Old Metal  UV Log.png

UV-Log, EL-NIKKOR 80mm f/5.6, old metal version
Attached Image: EL-NIKKOR 80 Old Metal  UV Log.png
General comments about the UV-reach:
reach


Filters and how to use them on this lens:
The front filter thread is rather odd, but suitable adapter can be found at RafCamera:
https://www.ebay.com...amera?_bkw=34.5

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, if space in the camera allows, is to putty-mount a filter directly against the lenses rear element mount ring.
The rear lens element is recessed and thus safe and the ring provides a good reference plane for orienting the filter normal to the optic axis.

My Omega 330W80 Improved Ø25mm, is mounted in a 27mm-filter ring and works well to mount as it is.


Handling and focusing:
This lens needs to be combined with a helicoid or macro bellows to set desired magnification.
With short enough minimum length of those it is easy to obtain focus at infinity even for DSLRs with long back-focus distance.
https://www.ultravio...__fromsearch__1

Flare and sun-stars:
NA

Sharpness:
I have found the lens impressing sharp all over the image field, but have no actual measurements.
My main usage has been for closeup UV and UV+VIS photography.

Lens distortion:
The lens

Chromatic Aberration / fringing in UV:
CrA

Image samples:
UV:

Filter:
UV, Fringing:

Filter:

UV, Fringing 100%:

Filter:

VIS+NIR:

Filter:

NIR:

Filter: long pass 800nm

Edited by UlfW, 06 April 2021 - 06:40.

Ulf Wilhelmson
Curious and trying to see the invisible.

#2 Andy Perrin

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Posted 03 January 2021 - 19:36

Quote

When using rear mounted filters it is important to realise that they shift the focusing to infinity as the filter-glass gives a shorter optical path length mimicking a forward shift of the lens.
In this case, while it's true the rear filters shift the focus, I don't know how important it is because it's on a helicoid anyway.

#3 nfoto

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Posted 03 January 2021 - 22:47

One just have to remember to focus *after* the filter is added.

#4 UlfW

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Posted 04 January 2021 - 01:16

Correctly noted. Thank you.
This is a spillover from the Sunex I missed to delete. That comment deleted.

This works like a group effort, with many observant eyes! Great!
Ulf Wilhelmson
Curious and trying to see the invisible.

#5 Andrea B.

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Posted 04 January 2021 - 18:27

Ulf, thank you again for these measurements. It is so good to have these charts.

I was wondering about that little bump between 300-310 nm? Is that just "noise" or is some transmission occuring?
Andrea G. Blum
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#6 UlfW

    Ulf W

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Posted 04 January 2021 - 19:31

View PostAndrea B., on 04 January 2021 - 18:27, said:

Ulf, thank you again for these measurements. It is so good to have these charts.

I was wondering about that little bump between 300-310 nm? Is that just "noise" or is some transmission occuring?

Yes It is just noise, no transmission here in the real world.
I have truncated tha data too far into the UV.
The bump should have been cut away.
Also the slight bend below and slightly above 1% is wrong. That is due to an offset caused by crosstalk.
The real λUV Zero is a few nm higher.

Today I think I have found yet another method to reach deeper into the noise to see a bit further of the attenuation, eliminating crosstalk effects.
My full spectrum graph is a composite of four separate measurements and a fifth setup and processing will improve both the dynamic range and how deep into the UV I can see.
At least I hope that will work. So far I have just made such measurements on the Nippon Kogaku-lens.
If theory holds after testing a few more lenses I will update the Log graphs and λUV Zero values

Edited by UlfW, 04 January 2021 - 19:36.

Ulf Wilhelmson
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#7 UlfW

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Posted 12 January 2021 - 08:42

The the improvement of dynamic range for the cut-on works.
Also improved the VIS and NIR measurements.
Updated the graphs and λUV Zero.
The same methods are applied to my other new lens posts too

Edited by UlfW, 12 January 2021 - 08:43.

Ulf Wilhelmson
Curious and trying to see the invisible.