• Ultraviolet Photography

Asahi Opt. Co. Super-Multi-Coated Takumar 1:3.5 / 28

UV Lens
4 replies to this topic

#1 Herman1705


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Posted 22 October 2016 - 23:12

Searched for a thread in the forum but could not find one on the Asahi Opt. Co. Super-Multi-Coated Takumar 1:3.5 / 28. Recently got this lens (back); I think I used it in the late 80's on a Pentax during a trip to Paris; moved 2 times in the meantime and knew that it had to be somewhere.

Some data:
Attached Image: Takumar-28mm_.jpg

(Have to clean the front Posted Image )
Attached Image: 20161022-DSC_8433.jpg

Attached Image: 20161022-DSC_8436.jpg

Attached Image: 20161022-DSC_8437.jpg

Blacklight lit ColorChecker; filters: stacked U340 (2mm) and BG40 (2mm); 45 s exposure:
Attached Image: 20161022-_DSC6643.jpg

Blacklight lit Strelizia; filters: stacked U340 (2mm) and BG40 (2mm); 30 s exposure:
Attached Image: 20161020-_DSC6587-2.jpg

I still have to do some fieldwork with this lens.
The images of the plant and the colorchecker show UV transmission. Anything known about the spectral UV range of this lens?


#2 nfoto

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Posted 23 October 2016 - 00:20

I'd be surprised if it goes any deeper than 380 nm or thereabouts. However, only field experience can indicate if the lens is useful for some kind of UV work.

#3 OlDoinyo


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Posted 23 October 2016 - 05:42

At least this is not one of the thoriated lenses.

You could do a pinhole test on the lens and compare the result to that using optics of more known properties (if you have them.)

#4 Andrea B.

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Posted 23 October 2016 - 17:13

That is a very long exposure time which would possibly indicate that there is some blockage of UV.
Andrea G. Blum
Often found hanging out with flowers & bees.

#5 Reed F. Curry


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Posted 23 October 2016 - 18:33

I have always been disappointed with the Takumars. Even those without Thorium-laced glass seem to have a yellow cast to the glass that inhibits UV transmission. Of course, seven groups doesn't help either; that is eight glass/air interfaces.
Best regards,