Asahi 35mm f/3.5 Super-Takumar

[ulf]

Last Update: 03 April 2021 agb/label

Finalized: Work in progress.

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Asahi 35mm f/3.5 Super-Takumar

 

Manufacturer: Asahi Opt. Co.

Lens Label: Asahi Opt. Co. Lens made in Japan Super Takumar 1:3.5/35 <serial number>

Currently manufactured: No

 

Lens type: Manual focus, Prime, Wide Angle

Design: 5 elements in 4 groups

Focal length: 35mm

Aperture range: f/3.5 – f/16, Preset Manual, 5 blades

Optimal magnification *: ?

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

Mount: M42 x 1 thread**, others. The mount is internally mounted on a T2 mount structure that can be exchanged between lenses

Helicoid: Yes

Flange Focus distance: M42/45.46 mm,

Front filter: 49 mm x 0.75 mm

Introduction year: 1959 as Auto-Takumar. With the same optical design for three versions named Super-Takumar, between 1962 and 1971

This lens produced: between 1964 and 1966 (version 2)

S/N of test object: 33858

 

More info, on the web: https://www.pentaxfo...-35mm-F3.5.html

 

Image of test object:

 

Transmittance Summary

Definitions of the parameters below

• Range: This Super-Takumar 1:3.5/35 lens transmits from 1-71% in an increasing slope from 333nm to 400nm.
• T_VISmax (%) = 87%
• T_400nm (%) = 71%
• T_365nm (%) = 47%
  This high percentage is an indicator for reasonably short exposure time under typical UV-pass filtration peaking around 360 nm or when using 365 nm UV-LED illumination.
• λ_{UV HMvis}(nm) = 363nm
• λ_{UV HM400}(nm) = 356nm
• λ_{UV Zero}(nm) = 333nm
• These three values indicate that the lens is working well for upper UV-A photography with suitable filters.

Spectral Transmission Graphs

UV-NIR, Super-Takumar 1:3.5/35

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

 

UV, Super-Takumar 1:3.5/35

 

UV-Log, Super-Takumar 1:3.5/35

Numerical Spectra Data available: Pending

 

General comments about the UV-reach:

This lens do not have a great UV-reach, but in the most common cases it still can be good enough.

If the sharpness is superior compared to other lenses, that might be a reason to use this lens instead of a less sharp lens with better UV-reach.

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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 sources on the web

 

Lens distortion:

TBD

 

Chromatic Aberration in UV:

TBD

[Andy Perrin]

I have the infamous 50mm/1.4 Super-Takumar with the radiation-yellowed glass. I take it this variant doesn’t have that issue.

[Andrea B.]

Well, this one surprised me a bit! I'm thinking that because it is an older Takumar 35/3.5, it probably does not have the stronger UV blocking coatings of the Pentax SMC versions.

[ulf]

I have the infamous 50mm/1.4 Super-Takumar with the radiation-yellowed glass. I take it this variant doesn’t have that issue.

I don't think so.

 

I recently got a geiger counter so I can check.

Beside my Canon FD 35/2.0 SSC I have not found any significantly radioactive lens

[ulf]

Well, this one surprised me a bit! I'm thinking that because it is an older Takumar 35/3.5, it probably does not have the stronger UV blocking coatings of the Pentax SMC versions.

It could be the glass types used that creates the cutoff, or possibly the cement in the cemented pair.

The very first version named Auto Takumar might be better. They can be found on eBay.

I can measure if someone pays for the lens. After the test I can forward it to the buyer.

 

For the moment I feel that my own need for more 35/3.5 is saturated.

There is no space left, not even for a thin slice of mint.

[OlDoinyo]

I think you may have posted the wrong graphs above.

 

I have been using this lens for a while in the UV, even though I did not originally purchase it for this purpose. It may not have bandpass equal to the best performers in this class, but it is very sharp and seems to have minimal focus shift or chromatic aberration. It is also very compact and takes modestly-sized 49mm filters. IR and visible performance are also surprisingly respectable.

[ulf]

I think you may have posted the wrong graphs above.

 

I have been using this lens for a while in the UV, even though I did not originally purchase it for this purpose. It may not have bandpass equal to the best performers in this class, but it is very sharp and seems to have minimal focus shift or chromatic aberration. It is also very compact and takes modestly-sized 49mm filters. IR and visible performance are also surprisingly respectable.

Thanks.

Corrected now

 

Originally it was the correct graphs.

When I later added indication lines at 365nm and 400nm to improve readability, I messed up.

All posts in the "normal" group should now have such lines, if I haven't made more mistakes.

 

That is nice to hear and what I hoped for when getting this lens.

[Doug A]

@ulf appreciate all the work put into these tests. I'll be on the lookout for one of these 35's. There is one discrepancy. The lens specifications list a 49mm filter thread. Under Filters and How to Use Them, 46mm is specified. 

 

Thanks again for all the tests and info,

Doug A

[ulf]

1 hour ago, Doug A said:

 There is one discrepancy. The lens specifications list a 49mm filter thread. Under Filters and How to Use Them, 46mm is specified. 

Thanks. Corrected.

 

Sometime in the future I hope to be able to add more meaningful evaluations and tests to all my Lens test topics.

Due to my personal situation it is not possible just now, but I am at least trying to design more suitable test setups, to be used.

It might take quite some time until I am able to do any real tests.

/U

[Bill De Jager]

Thank you for your work on this, Ulf. I have one of these stashed away unused and untested.  I'll keep this lens in mind for future use.

[photoni]

@ulf Thank you for your work :)

[ulf]

You'r welcome Tony,

 

I think it is interesting working with measurements. It is one of my hobbies beside UV-photography.

[photoni]

Cherry trees in bloom

from IR to UV with Asahi S.T. 35 f3,5     @ f:8

 

these white cherry blossoms turn blue / purple in UV
a nearby plant with white pear blossoms, turn black

 

 

[Yon Marsh]

Some interesting results Tony, thanks for doing all these informative lens tests Ulf

[ulf]

1 hour ago, Yon Marsh said:

Some interesting results Tony, thanks for doing all these informative lens tests Ulf

I find it interesting to optimise measurement methods and have enjoyed doing of it, most of the time. 

 

I have intended to publish results from a few more lenses, but have no time to do that now.

My life has become overfilled with other very important things to do for the moment.

 

There is not even time for any UV-imaging of flowers that I like to do very much.

Maybe next year...

 

I also had an ambition to expand the information for all tested lenses beyond the transmission measurements, by creating suitable test setups for other characteristics of the lenses performance. However those setups are still just seeds of ideas.

 

I hope to be able to continue with those idea some day in the future.

[JCDowdy]

I can sympathize with that!