Saturday, July 28, 2012

Petri Kuribayashi f3.5/35mm lens for reflected UV photography

Now this today was based on an information I got from a forum,  that the Petri Kuribayashi f3.5/35mm lens was very capable of working for reflected UV photography.

I tested that lens and it performed even better (pink line) than the well known Noflexar f3.5/35mm lens (red line), reaching down into UV to about 320nm. At 365nm it even has a 12% higher transmission (1/4 stop).

[click on image to see a larger one]

There are a few similar looking re-branded emanations of that Kuri lens, but with lesser performance, so be aware of that. These and a few other emanations of basically the same lens were not my finds, but Boon Tang and Alex Holovachov deserve the credit for those finds and bringing it to my attention. I'm not sure if later made models may have the same good transmittance, as the coating may have been changed to more modern ones that unfortunately suppress UV to pass (blue coating color is an indication for that). Here for instance the Prinzgalaxy f3.5/35mm in comparison, that shows a about 20% lower transmission at 365nm, but still useful (1/2 stop less):

And here one of SOLIGOR brand:

Here now a quick photographic test of that original Kuribayashi 35mm lens, which shows virtually no focus shift (1.03%), as well as very good sharpness and very good contrast in reflected UV using the Baader-U filter:

Here the visual shot for comparison:

The little downside that it only focuses to about one meter (3 ft) can be overcome by using a small helicoid or tube, if so needed. Here the Noflexar 35mm has an edge, as it has a built in close focus ability to about 1:2 (0.5x) magnification.

So this "zebra" barrel styled Kuribayashi lens from the 50ies / 60ies is a very welcomed new lens to the very few "normal" i.e. non quartz fluorite ones that does perform very well.

There is a part II about this lens HERE.

Photographic comparison between the Kuribayashi and the Soligor lens is HERE.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site

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