17 replies to this topic

[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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Novoflex 35mm f/3.5 Noflexar

Manufacturer: Novoflex / Staeble
Manufacturer's lens designation: NOFLEXAR 1:3,5 / 35
Currently manufactured: No

Lens type: Manual focus, Prime, Wide Angle, Close-Up (to 1 : 2 with built-in click-stop extension)
Design: 4 elements in 4 groups
Focal length: 35mm
Aperture range: f/3.5 – f/16, Preset Manual, 10 blades

Recommended magnification range: Up to 1x without reversing the lens.
Optimal magnification *: ?
Sensor format/coverage: up to 24 mm x 36 mm

Mount: M42 x 1 thread, Exakta, Nikon, Zenit (COWEIT, EXWIT, NIKWEIT, ZENWEIT)
Helicoid: Yes
Flange Focus distance: M42/45.46 mm, Exakta/44.70 mm, Nikon F/46.50 mm, Zenit/47.58 mm
Front filter: 49 mm x 0.75 mm

Introduction year: between 1960 and 1969???
S/N of test object: 356594

Lens review (VIS), on the web: https://www.pentaxfo...r-f35-35mm.html
Lens brochure on the web: http://www.macrolens...Makro_en_02.pdf

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Image of test object:

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Transmittance Summary
^{See definitions at https://www.ultravio...ion-parameters/}

• Range: The Noflexar 35/3.5 lens transmits 0-70% in an increasing slope from 322nm to 400nm.
  
• T_VISmax (%) = 89%
  
• T_400nm (%) = 74%
  
• T_365nm (%) = 58%
  This high percentage is an indicator for relatively short exposure time under typical UV-pass filtration peaking around 360 nm or when using 365 nm UV-LED illumination.
  
• λ_{UV HMvis}(nm) = 352nm
  
• λ_{UV HM400}(nm) = 347nm
  
• λ_{UV Zero}(nm) = 321nm
  
• 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.

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Spectral Transmission Graphs
UV-NIR, Novoflex 35mm f/3.5 Noflexar

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

UV, Novoflex 35mm f/3.5 Noflexar


UV-Log, Novoflex 35mm f/3.5 Noflexar

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:
The front filter thread is 49mm 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, 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.

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Handling and focussing:
TBD

Flare and sun-stars:
TBD

Sharpness:
High according to net reviews. For UV ?

Lens distortion:
TBD

Chromatic Aberration in UV:
TBD

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Image samples:
UV:
image
Filter:

UV, Fringing:
image tba
Filter:

UV, Fringing 100%:
image tba
Filter:

VIS+NIR:
image tba
Filter:

NIR:
image tba
Filter:

[Andrea B.]

Ulf -- a minor comment: I think that the Transmittance Summary should be followed by the Transmittance charts.
Your feedback on this?
I am happy to tweak that if you agree.

spelling: handeling --> handling

The usual way of writing filter thread diameter and pitch is with an 'x': Example 45 mm x .75

Something important which we must add is whether the lens is currently manufactured.
I'll do that for the existing Lens Data entries.

Important for the Lens Type is whether the lens is manual focus and prime or zoom.
Let's nail down an order for mentioning facts in Lens Type, OK?
Example: tele/wide-angle/close-up/whatever prime/zoom manual_focus/auto_focus/fixed_focus

I was wondering if the notation for the half-max relative to the Visible max
might better be denoted λ_{UV HMVis}(nm) or λ_{UV HMvis}(nm)
That way it is immediately obvious to what the half-max is relative.
Ulf, your feedback on this?

[UlfW]

Thanks for the observations and corrections.
You are completely right about the order. I fixed that.

I am OK with all suggestions except maybe the one about filter thread specification.. Skipping both the leading zero and the unit looks plainly wrong to me.
This would look better to me: Filter-thread/-mount: 49mm x 0.75mm

I have also felt that it would be better if the definitions of the parameters were removed and placed in a separate document and not repeated for every test.
A simple link to the definitions document would be much better. OK?

Please feel free to do all changes to the documents

I have also added a discrete line in most UV Lens Data posts:
Numerical Spectra Data available: Pending

When Pending is replaced with a "Yes" I have the data

I intend to share it to forum members, but only on request.

The data has a format with integer wavelengths, comma separated to the transmission data.


This way the transmission information is possible to use in the Schott filter "program" and be combined with other filters to get a view of how different Lens/filter combinations will behave.
There are just a few simple operations to do in Excel to the data before pasting it into the Schott filter "program" in a user filter column.
I will add information how to do the data transplant in a separate text document. that I will share too.

I have done this with the data from my Baader U measurement and it works just fine.

Edited by UlfW, 12 January 2021 - 21:41.

[Andrea B.]

By all means add the leading zero and the units for such things as 45mm x 0.75mm.
I meant only to suggest the 'x' format.

You can write a topic explaining the transmittance summary definitions and I will "pin" it to appear as the lead topic. Then you can remove the definitions from the separate topics.

[UlfW]

Andrea B., on 12 January 2021 - 18:16, said:

Let's nail down an order for mentioning facts in Lens Type, OK?
Example: tele/wide-angle/close-up/whatever prime/zoom manual_focus/auto_focus/fixed_focus

That can be a good idea.
Let us discuss that format.
Look at the changes I made above for this.
For the Novoflexar 35/3.5 I just quoted the definition from Novoflex documentation.

Edited by UlfW, 13 January 2021 - 07:57.

[Andrea B.]

Note: I will move these formatting comments later.

Whatever order you like is fine with me.
So we have:
1) manual_focus/auto_focus/fixed_focus
2) prime/zoom
3) super_wide_angle/wide_angle/standard/telephoto/super_telephoto
4) additional characterizations

[UlfW]

You forgot the different aperture types
Fixed, manual, preset manual, automatic-mechanical, automatic-electronic only
I think the Canon EF 40mm is of the last type and might be difficult to use not wide open without a camera controlling it
Also the number of aperture blades and shape might be interesting for the bohke.

[JCDowdy]

UlfW, on 11 January 2021 - 12:45, said:

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Handling and focussing:
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.

This needs to be revised. It appears to simply be an overlooked copy paste error.

[Andrea B.]

Thanks!

*****

You forgot the different aperture types
Fixed, manual, preset manual, automatic-mechanical, automatic-electronic only

I think I would list that with aperture range.

[UlfW]

JCDowdy, on 13 January 2021 - 23:33, said:

This needs to be revised. It appears to simply be an overlooked copy paste error.

John,
That is the reason the first line reads:Finalized: Work in progress.

It is not an error, but a placeholder for a section that should eventually be filled with content.
You see similar things in all of my later UV Lens Data posts
Maybe the unfinished parts should be highlighted in some way indicating just that.
Can a simple TBD be enough?
I just aded that under Handling.

I do not see these documents as static and even when the are more complete and marked as finalized I am quite open to adding more information of someone wants to contribute in a comment.

It is OK to contribute information about the lens in a comment to be integrated into the first post.
It would be great if this UV Lens Data section could be a group effort.

If you have the lens and want to contribute, please suggest some content.
I have been busy with the transmission measurement parts.
I have not used my Novoflexar35 that much but have indeed experienced the light leakage problem from the lens extension mechanism.

Edited by UlfW, 14 January 2021 - 08:31.

[UlfW]

Andrea B., on 14 January 2021 - 03:09, said:

Thanks!

*****

You forgot the different aperture types
Fixed, manual, preset manual, automatic-mechanical, automatic-electronic only

I think I would list that with aperture range.

Good idea. Done.

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Sometimes one find cross sections showing the lens structure.
Where do you think such images should be placed in the document?

What do you think about the empty lines in the first information list in this lens entry compared to some of the others without empty lines?
They section off more related information in sub-groups making them easier to find, but at first sight a straight list looks prettier to me.
I cannot decide what is best.
Your opinion?

Edited by UlfW, 14 January 2021 - 08:38.

[JCDowdy]

Yes, TBD is preferable as a placeholder in the template.

I also like the links out to additional lens review and brochure.

[Andrea B.]

Thanks for the feedback!
**********

I'll add a line at the top of each topic saying contributions from everyone are welcome and will be incorporated into the topic with attribution.

I will probably remove the formatting comments from each thread. There are a lot of those as we get started but they will not be relevant as Ulf's work progresses.

[Andrea B.]

Ulf, I am looking at my Noflexar now and see that the rear element is not recessed. So I think the comment above is in error about being able to rear mount a filter?? (above meaning Filters and how to use them on this lens)

[Andy Perrin]

Andrea, pretty sure it's not a problem to rear mount on a Noflexar (I think I've done it before). Possibly it's only an issue for you because you don't have mirrorless?

Example:
https://www.ultravio...dpost__p__12823

Edited by Andy Perrin, 14 January 2021 - 22:17.

[UlfW]

The lens surface of the rear lens element is definitely recessed below the mounting ting of the element allowing rear mounting.
However for DSLRs there might not be space enough for rear mounting.

[Andrea B.]

JFTR, I have at least 3 mirrorless conversions (Sony A7R, Lumix G-something, Lumix S1R).

Not to be contentious here but I repeat -- I am looking right now at an F-mount Noflexar 35/3.5 which I CANNOT set on its mount end without the lens "rocking" because the rear element is NOT recessed and protrudes a bit beyond the mount ring. Don't want to test that "rocking" further 'cause it's scary to set a lens down upon a non-recessed rear element!!)

Therefore, if all agree that the Noflexar rear element is recessed, I am thinking that perhaps this particular Noflexar must be some type of conversion from another mount?? So I will try to look thru my purchase records (such as they are!! like in a bit of disarray) to see whether I can find if that is the case. It would be the only thing which explains this non-recessed rear element Noflexar?

Update to follow sometime today.

Added: The issue here is not rear mounting, but rather the protrusion or not of the Noflexar rear element. Just to make sure everyone knows that I agree: protrusion of a rear element does not necessarily affect rear mounting of a filter.

[Andy Perrin]

Andrea, in mine, the Noflexar's rear element sits inside the M42-Sony lens converter with tons of space. If I unscrew the lens from the converter then it does protrude, it's just never an issue for me because I can't use it without the converter anyhow! I think it's just not going to be an issue for mirrorless camera folks and possibly an issue for the DSLR crowd.

Edited by Andy Perrin, Yesterday, 20:33.