NikonGear'23
Images => Nature, Flora, Fauna & Landscapes => Topic started by: armando_m on October 19, 2017, 05:15:24
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I got an invitation to shoot some corals,
the light used to get the more vivid colors is near uv
I'm using my regular d800
I'm wondering that a fixed wb will be better
Anyone has any recommendations?
The corals are about 10cm across
so it will likely not require a macro
Thanks in advance
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Apparently you will be going to shoot corals under the visible light with the additional ultraviolet-induced visible fluorescence (which should be the main purpose of the use of the near-UV lighting).
I haven't heard about the suitable WB for that. The best way would be, as always, to shoot RAW and try different WB settings in the post process.
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Thanks Akira
yes I'll shoot Raw
Hopefully I get something interesting and worth sharing
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I don't know anything but I'm wondering if it wouldn't be smart to check the tri-color (RGB) histogram to make sure that no channels get blown or clipped. I'd shoot with the Neutral PC and then add whatever punch you want in LCH using Master Lightness for contrast and Chroma for saturation. Starting from an NEF in neutral you can still knock a person's eyes out with eye candy or be quite subtle as you choose.
That's my 2 cents,
Dave
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Thanks Akira
yes I'll shoot Raw
Hopefully I get something interesting and worth sharing
I'm looking forward to seeing the results!
I think that Dave's advise should make a lot of sense. Also, you may be better to bear in mind that the overall lighting can be dimmer than expected in order to balance the fluorescing light and the reflected light. The pure fluorescence is definitely dim.
If you have a chance to shoot pure fluorescence, and the "near-UV" light emits only small amount of visible portion, then you may want to use a light yellow filter to cut the influence from the near-UV light to cut the reflection from the light source. The corals fluoresce mostly in light green:
https://www.flickr.com/search/?text=coral%20fluorescence
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So am I, looking forward to your results.
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I'm not sure if this is of any help, but when I'm using my Baader-U filter to shoot the UV spectrum my white balance is bottomed out, so to speak, at 2000k.
If the light will be bright enough and you're using a camera with live view I would suggest to turn on live view and set the WB to 2000k, then dial it up through 10000k and set it to where it looks best.
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Charlie, you are talking about capturing the UV-reflected light using UV-pass lenses and UV-modified camera, which is totally different from the UV-induced fluorescence which is visible, as you know.
Armando is going to deal only with the visible spectrum using normal camera and lenses.
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I have so far usually kept automatic WB when I work with UVIVF, however when I have checked them out with daylight WB in CNX2, they become very similar to what the camera chose for me. I only have a Nikon L39 on the lens.
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I used an orange filter to block the strong blue light
While I shot with a warm WB, in PP I used daylight 5200
This were shot in a store, the owners are friends to a friend who is a biologist (remember the blue mushrooms I shoot?), a shipment of new corals was just received, it is like eye candy with all the incredible colors and shapes
Shooting conditions were complicated but seems I still was able to get a few usable images
I have not looked at all of them but here is one I liked, the blue shadows are likely tentacles blurred due to a longish exposure
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Armando - Very striking photo - brilliant neon colours from the natural world! Thanks for opening the discussion and posting this result. One minor comment - it might be worth placing some black card or cloth over the back of the tank to remove the distracting background (upper right corner).
Cheers - John
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Thanks John yes , I did not see the background while shooting ::)
Here is one shot without the orange filter, a bit of work to remove the strong blues
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Armando:
I don't know which software you use but there is a very easy way to neutralize the purple/blue cast by simply desaturating those colours:
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Oh, thanks Armando!
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Armando, the first image looks promising, although I would have to agree about the treatment of the background.
Ann's correction for the second image makes sense, but maybe the UVIVF in light green looks less prominent?
How about this? I opened Armando's posted JPEG in the latest ACR, with Exposure +0.50, Contrast +50, Highlights -100 and Clarity +10.
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Paco de nada
I'll process more later
Thanks Ann , I thought I had removed must of the blues, I used cnx2 and Ps cc/acr, but obviously didn't remove it completely, seems you also increased the exposure a bit?
Thanks for taking the time to post your edit
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I don't remember exactly what edits I made (and I have already trashed the file so can't check!).
I just downloaded the file from the NG page but I do remember that it didn't have an embedded Profile so I assigned it an sRGB profile and would have probably have done a quick Auto Tone after that so that the image looked normal on my screen.
Then I went into ACR's HSL Panel and pulled the Purple Saturation slider back considerably.
You could almost certainly do a much more refined job than I did by doing the Purple-desaturation in a Layer-Masked Layer.
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Sorry, that got posted in the wrong thread!
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I got an invitation to shoot some corals,
the light used to get the more vivid colors is near uv
I'm using my regular d800
I'm wondering that a fixed wb will be better
Anyone has any recommendations?
....
Is there anything in any of the images approaching near white or grey or black?
If so, use one of those areas as a reference point for a grey point in the WB tool.
Do you use ViewNX2 as well or just CNX2?
Same thing with the WB tool.
I find using the grey point for WB choice usually makes a nicer overall WB rendering.
Once you get close to how you want them to render in terms of WB, then in CNX2(VNX2 doesn't have this... ) use the Selection Control Point tool(not colour control point) on any areas that still look too blue/purple for 'ya.
Obviously you enlarge/decrease the area for selection, and in the selection properties type in the tool you choose Colour-> Saturation/Warmth and desaturate as required and warm it as required.
If you have a sample NEF file I could test with, I can try to help.
Many years back I was asked to attend a body art show and they had a UV fluorescence session where the folks were all lit under very strong UV light .. but little other visible light.
I just used a grey point for my WB, on a white towel in some of the images, and the very strong purple WB rendering all but vanished. Very easy to do and then applied to all images.
I just went back to some of those images to check what the whitebalance values ended up as .. and you could try these as some start points to play with.
So in CNX2 on an NEF file: Go to WB tool in the Develop tab. Change the Set Color Temperature to Set Grey Point. Once you do this, you are then presented with a dropper tool option AND the option to type in values into the red/blue channel.
In the red/blue channel try these two values as a start point.
Red = 2.2 : Blue = 0.2
Note they can be adjusted from 0.1 - 10 lower meaning less, higher meaning more.
Those two values gave me a white towel rendered white under mainly UV light(at about 390nm).
As you have some non UV ambient to deal with too, I'd say you've going to need to lower red and increase blue by comparison.
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Arthur, thanks I had forgotten about the WB marquee sample, it works like a charm , I used the sand to create the gray sample, which it likely is not 100% gray, and a proper gray card would work better
here is a before and after