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UltravioletPhotography

Question about Kolari Filter Test


Andrea B.

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For this filter comparison test (link below) the Nikon 50/1.8D AF lens was used.

Do you think that a dedicated UV lens should have been used?

I don't really know the answer, but I think I would only perform

a test like this with a dedicated UV lens.

 

This would be a good test to repeat with the UV-Nikkor or some other good UV lens

to see what we get.

 

https://kolarivision...uv-filter-test/

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The shooting data for the outdoor scenes indicates the used lenses (or filters?) are not that well transmitting in UV, despite all Kolari claims to the opposite. f/4, 1600 ISO, 1/6 sec to 1/10 sec is bad.

 

However, if all there is required to show people have sunspots or flowers display a dark centre, the Kolari setups can function.

 

A real pity they don't publish the spectral response chart for their special UV bandpass filter, though. Such information should never be considered a "trade secret".

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There is something on that web page that looks like spectral transmittance charts, albeit without proper labeling. Am I mistaken?

 

I wonder at the fogginess of the images from the middle filter. Is it a scattering effect? Stray light leaking around the mount? Adhesive fluorescence? We do not see it in the images from the separate stacked filters. If the problem is adhesive fluorescence, using the filter with the BG side out rather than facing the sensor should take care of it.

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That is not the test made by Kolari.

 

The graphs look more like histograms to me.

 

I think that post causes more questions than it answers.

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I'd like to see the log (diabatic) graph. Now we mainly learn that the filter is not letting much UV through. One to two stops below a standard Baader depending on spectral properties of incoming UV illumination and lens used.
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I'd like to see the log (diabatic) graph.

 

Agreed!!!!!

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LUV and Baader. 1600 wide.

 

LUV

post-87-0-65135200-1496637604.jpg

 

Baader

post-87-0-26184000-1496637638.jpg

 

I'd be happy to send the guy a new filter, but I have no idea what is going on with his results.

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I would also be happy to exchange filters with Kolari, and do independent comparisons on our own, because I highly discredit the results shown by someone on their site.

I have never experience such results when comparing the Baaader U and the LUV U.

The 'cloudiness' and un-sharpness that Pierre-Louis = DonPilou has shown, I have never seen such results.

I would never be selling them if I got results like what was shown on the KOLARI site by Pierre-Louis (DonPilou).

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I'd like to see the log (diabatic) graph. Now we mainly learn that the filter is not letting much UV through. One to two stops below a standard Baader depending on spectral properties of incoming UV illumination and lens used.

I'd like to see the log (diabatic) graph.

 

Agreed!!!!!

 

I started to say this yesterday also!

 

Sometimes I suspect the use of linear scale filter transmittance plots is to intentionally conceal out of band "leaks".

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The flower pictures with the Kolari and the LUV filter have slightly different focus settings and further the "dark" areas of the pictures got a different "exposure", the dark area in the picture taken with the LUV is brighter (there is no black).

Further it would be nice to know, whether a hood was used.

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Well, we all agree that DonPilou's test seems inaccurate.

But I don't want to haul out the pitchforks and torches just yet !!!

 

1.) The Kolari UV-pass filter is good. I've made a few runs with it. It has a good price and many buyers will benefit from that. I agree that complete information should be supplied about the OD leaks.

Link: http://www.ultraviol...-straightedgeu/

 

 

2.) Testing UV-pass filters is an art, not a science UNLESS one has access to spectrometers, etc. So I'm not going to criticize Don Pilou too much for his testing attempt. But I think I will try to remedy the situation by contacting Don Pilou and suggesting alternate ways to test. Perhaps he could remove the comparative parts of his write-up and simply leave the Kolari filters as an illustration of the Kolari "look".

 

3). I personally think that we should all recognize that a "foggy" filter is never purposefully sold, especially by our vendor-members Cadmium or Reed or any other reputable filter vendor that I know. If some filter you own becomes foggy, then likely it is unclad and has oxidized. You can maintain oxidizable filters for a few years via various cleaning & polishing methods. Also, clad or polished filters eventually become scratched, etc. When one of my filters has problems which can affect the photo, then I'm not going to use it unfairly in a test.

 

4.) Any filter will flare under the right circumstances. Use of a hood to remedy flare is suggested. I don't know if that is the issue with Don Pilou's photos or not.

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Just my 2 cents:

 

Baader U - f/11, Aperture Priority, ISO 200, 2.5s Marquee WB

post-87-0-11380000-1496696388.jpg

 

LUV U - f/11, Aperture Priority, ISO 200, 3s Marquee WB

post-87-0-33432400-1496696400.jpg

 

La La U - f/11, Aperture Priority, ISO 200, 3s Marquee WB

post-87-0-72176400-1496696421.jpg

 

MOON U - f/11, Aperture Priority, ISO 200, 2s Marquee WB

post-87-0-87965800-1496696433.jpg

 

No post processing other than marquee.

Lens: Kuribayashi 35mm.

All identical settings other than exposure time.

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Just to compare detail, here are the 'Actual Pixels' crops from each shot above. I used my D7000 UV/IR for these.

 

Baader U

post-87-0-91552700-1496699263.jpg

 

LUV U

post-87-0-39474200-1496699288.jpg

 

La La U

post-87-0-29865000-1496699310.jpg

 

MOON U

post-87-0-68541600-1496699330.jpg

 

All

post-87-0-86996800-1538012473.jpg

 

By the way, how come DonPilou's original UV portrait pics using the LUV U looked very nice compared to the examples he shows on the Kolari page?!

I don't personally like the white balance he uses, but that is a personal choice, and they still look very nice.

http://www.ultraviol...h__1#entry12536

 

http://www.ultraviol...h__1#entry13468

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For those who asked, the LUV U2 issue has been discussed in private with Andrea and Cadmium, and the problem is going to be solved.
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