Seeking advice for a novice UV Photographer

[ahrneely]

Hello, Ladies and Gentlemen. This is my first post here at Ultraviolet Photography. I have spent a lot of time reading through all of the various posts available already, and I am impressed by the amount of information available on this forum. However, I still have some additional questions (and, being more of an artistic personality than a scientific one, I am having difficulty coming to certain conclusions).

 

Here it goes: I am just starting out in the world of UV Photography. As I stated in my introductory post here, I am interested in creating UV Portraits. However, as I am new, I am starting slowly. With that in mind, I have purchased some equipment that I think should help me get into the world of UV photography, but I don't seem to be quite there yet.

 

I have had a company called LifePixel convert my Canon 20D into [what is known on this website as] a "broad-spectrum" camera (they call it a full-spectrum camera). This is my only camera body capable of capturing any type of UV light.

 

I have also gone out and purchased (used on eBay) an El-Nikkor 50mm f/2.8 enlarger lens and an adapter ring (M39 thread mount to Canon EOS) and bellows to fit the lens to my camera body. Additionally, I have also purchased (again, used on eBay) a B+W 403 UV Pass filter and a Tiffen Standard Hot Mirror filter.

 

I realize that the B+W 403 filter does leak some infrared. I also realize that the Hot Mirror filter also leaks some infrared. My hope was, with the two of them together, I'd be able to cut enough of the infrared to not have to worry about contamination, but I'm beginning to think this is not the case.

 

I don't yet have the funds available to purchase the coveted Baader Venus U (it is on my list, however). Does anyone have any other suggestions of a less-expensive way to go to begin capturing RAW UV images? Perhaps a different IR Cut filter that I don't know about yet?

 

I have scoped out the filter section, but a lot of what I see there have dead links or refer to glass types that, when Googled, seem to lead me nowhere.

 

I do have two additional questions (which, perhaps, should be in a separate post - please let me know if I should make that correction):

 

1. Do flowers need to be "alive" in order to reflect UV light? There is often quite a bit of wind where I live, so picking a flower and bringing it indoors to photograph is helpful, though I'm sure there is far less UV light indoors, so I have a conundrum there.

 

2. I have Capture One for my white balancing (as we all no ACR doesn't work very well in the non-visible spectrum). Is there a certain color temperature I should be aiming for in my UV photographs (once I finally achieve them)?

 

This is a JPG of the RAW capture before any white balance. This was taken in mid-morning sunlight on a boat dock above water (I'm sure there was some reflectivity). She is holding a MacBeth Color Checker Chart (as well you know). It was shot with the B+W 403 stacked with the Tiffen Hot Mirror. I wasn't sure if including the image would help troubleshooting at all. I assume I'm still seeing quite a bit of IR leak.

 

Thanks again for any advice.

 

Ahr Neely

[nfoto]

To me this looks like an IR photograph. Do note the foliage is bright which is counterindicative for true UV.

 

So, the recommendations are to use a better filter for UV.

 

Flowers don't need to be shot "in situ" as long as there is sufficient UV to illuminate them.

 

As to processing software, each appears to follow their own principles. PhotoNinja usually ends up at 2000 K and tint -60 or thereabouts when using a Baader U2. Aftershot Pro won't reach proper w/b for UV even at 1667 K (lowest available) with the same filter.

 

Try a trial version of PhotoNinja.

[Andrea B.]

Hi Ahr !!!

 

Thank you for pointing out that there are dead links in the Stickies. I have put that on my ToDo list to fix them.

 

Let me tackle your questions:

 

1. UV-Pass Filters

2. Live flowers and Shooting UV Indoors

3. Converters/editors, UV White Balance and Temperatures

 

UV-Pass Filter Options

 

The B+W 403 and Tiffen Hot Mirror will not work well because the Tiffen Hot Mirror leaks too much IR to be an effective IR blocker for an IR-leaky UV-pass filter.

It is possible you can combine the 403 with another kind of hot mirror such as an S8612 or BG39. Let me test that out and get back to you, OK? We'll see if we can find something to make the 403 work.

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UPDATE 18 July 2013 4:27PM Eastern Daylight Time, USA

If you stack a B+W 403 with either of two following types of glass, the combo will work well for UV photography. The exposure times might be slightly longer than with a single dedicated filter.

• BG 39
  
• S8612
  

My S8612 filter is 1.75mm thick. My BG 39 filter is made by B+W. I don't know how thick it is, but it could be looked up.

 

If you go look at this thread, it shows the results of my experiments with the B+W 403. Two of the photos there were made with the 403 stacked with the above.

http://www.ultraviol...igure-them-out/

 

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Here is a price list on 4 UV-Pass filter options which we know work well.

 

Baader-U: $360, needs step rings

Precision-U: $249, 52mm size. UVROptics: http://www.uvroptics....php?PrecisionU

 

Hoya U340 + S8612 Stack: $145+75 = $220 for 52mm sizes,

Hoya U360 + S8612 Stack: $70+75 = $145 for 52mm sizes.

Seller: uviroptics on Ebay http://myworld.ebay....=p2047675.l2559

 

These Hoya filters are also IR-leakers so must be combined with IR-blockers like Schott 8612 or BG39. The price for filter stacks can vary depending on the thickness of the filter ordered. You need the IR blocker to probably 2mm thick to sufficiently block the IR. In additon to the U340/360, you can also get Schott UG glass such as UG11 to combine with S8612 or BG39.

 

As Bjørn has pointed out your trees are bright - sure sign of IR contamination. In UV most foliage is UV-dark. Keep this in mind when testing filters.

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Live Flowers and Shooting UV Indoors

 

Yes, you can pick a flower, put it into a bit of water and bring it indoors to shoot. All objects retain their UV reflectivity/absorption indoors or out.

 

However, there is often not sufficient UV illumination indoors to make UV photographs. My old windows pass some UV, but newer window glass does not. To shoot UV successfully indoors you would eventually need a UV flash of some type if your windows do not provide any. You will just have to test things out in your own place to see if UV is possible indoors. Experiment !!

 

There are also some UV-LED flashlights available, but most of those do not put out a lot of UV. Sunlight and UV flashes provide a wideband UV. Note that UV-LED flashlights emit a narrower band of UV - peaking around 365nm. Some UV-LED flashlights peak around 400nm - those emit too much blue.

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See next post for remainder.

[Andrea B.]

Converters/editors, UV White Balance and Temperatures

 

Just make your UV photographs look good by your standards. Because all colour in a UV foto is False Colour, you are free to play with it as you wish. There is no need to white balance unless you simply wish to do so.

 

Here you will see that Bjørn and I present our botanical fotos in standardized colours because we use many different camera + lens combinations. So our raw fotos differ in their False Colours. A UV-signature is invariant, but False Colours are not! We standardize so that the same flower photographed with different equipment would appear the same. Worth repeating --> standardization or white-balancing does not change a UV signature. It only changes the False Colours in which the UV-signature is presented.

 

If you do wish to White Balance your UV foto using a "click-white" tool, you will find that the Temperature shoots to the extreme left end of the Temp scale. Depending on which converter/editor you are using, you will see Temps from 1700° - 2000°. And any Hue or Tint slider will change as well, but changes there depend on the native colours of your particular camera.

Update: 18 Jul 2013 5:57PM Eastern Daylight Time, USA For some of the UV-Pass filter stacks I have been testing, the Temp does not go as far down. I have gotten some Temps of 2200 - 2600° for these stacks.

 

Note that when using a click-white tool for UV work, it is best to set the sample fairly large.

 

I need to go check whether any of the Color Checker patches work for white balancing a UV foto. I think they don't work so well because most things do not retain the same reflectivity in UV that they have in Visible light. However, the CC might get you close. I'll get back to you on this too, OK?

Update: 18 Jul 2013 6:03PM Eastern Daylight Time, USA

See this thread: http://www.ultravioletphotography.com/content/index.php?/topic/479-the-color-checker-passport-and-uv-an-interesting-discovery/

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That's all I got right now. Hope it helps!! :D

[ahrneely]

Andrea and Bjørn:

 

Thanks so much for the information. This definitely helps...a lot! I think what I'm going to do is save my pennies for the Baader-U, and stop messing around with "cheaper" work-arounds. This appears to be the best option. I could spend a ton attempting to find a "cheaper" solution that won't work as well as what has been tried and tested.

 

For now, I'll simply work on some artistic work in the IR and Full-Spectrum ranges until I can find a good Baader-U filter.

 

I totally appreciate the thorough responses. That was amazing!

 

Andrea, I do have one further question for you. In the Ultraviolet Fauna section of the forum, you have a photograph of a frog. The exposure differences between the visible light and the UV light for the frog are extreme (6-stops). I'm curious how you were able to obtain such lack of motion blur from the frog and swampy water with such a long exposure. Surely it must have been a super calm day and the frog didn't move that entire time. It is not a UV related question, specifically, but I am impressed by the clarity of such a long exposure in an uncontrolled environment.

 

Thanks again!

 

Ahr

[Andrea B.]

I wouldn't discount a filter stack made up of your 403 and an S8612. It is good and would let you get started. Then once you had a Baader-U, you could have the 403-8612 as a backup. Somewhere there is a photo of my crushed Baader-U which definitely illustrates why backups are nice.  I hope that never happens to anyone else!!

 

*****

 

It is definitely true that the frog did not move. That seems to be the case mostly, that they sit there immobile. So if you are able to sneak up quietly on the froggies, then you can usually get a UV shot if there is sufficient light. One wrong move, however, and they dart back into the water so fast!! And of course it is useful to crank up the ISO setting in such circumstances.