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09-15-2012, 08:41 AM   #166
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QuoteOriginally posted by UnknownVT Quote
Good luck.
Thanks for the reply. Looking at your work, I clearly still have much to learn.

I will talk to some of the lighting guys who do a lot of the local venues about going easy with the mono-coloured LED lighting in future, at least for the spots aimed at the main performers. I live in hope. Those big mono-colour washout shots are really hard to do anything decent with.

An idea I might put to the lighting crew is to ask them to stick a small patch of 18% grey (or close equivalent) tape on the mic stands or mic grips, or stick a small 18% grey card or two somewhere visible on the gear on stage, so that when PP'ing an image photogs like me will have a more predictable WB target to work with.

What's your view on that idea?

As an aside, I'm also curious about how 'pro' photogs who do this for a living manage the problem, especially those who are on staff to supply publicity shots.

09-15-2012, 09:06 AM   #167
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QuoteOriginally posted by rawr Quote
An idea I might put to the lighting crew is to ask them to stick a small patch of 18% grey (or close equivalent) tape on the mic stands or mic grips, or stick a small 18% grey card or two somewhere visible on the gear on stage, so that when PP'ing an image photogs like me will have a more predictable WB target to work with.
That's a good idea - it will do much for the part of the stage lit the same way as the gray-card.
Then the only thing to contend with is that they don't change the lights on you after you've gone to the trouble of manually setting your WB and just about to shoot

However there is a caveat - this is to do with the discrete nature of LEDs - since they do not give a smooth spectrum even though "white" may appear that way to our eyes our cameras can tell the difference - so even though one may set a WB with a gray-card - because of the imbalance between RGB - or severe lack of one color could still give us unnatural looking colors/WB.

I had an earlier post #140 that has explanations and links.

QuoteOriginally posted by rawr Quote
As an aside, I'm also curious about how 'pro' photogs who do this for a living manage the problem, especially those who are on staff to supply publicity shots.
I shoot along side of pros all the time - for strong mono-colored lights a lot complain to the main act or promoter who talks to the lighting person -
I do not have such clout - and rely on mostly showing the lighting person GOOD looking shots only - as a praise, and hope that positive reinforcement works.

Last edited by UnknownVT; 09-15-2012 at 09:13 AM.
09-15-2012, 10:15 AM   #168
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QuoteOriginally posted by UnknownVT Quote
Then the only thing to contend with is that they don't change the lights on you after you've gone to the trouble of manually setting your WB and just about to shoot
Too true.

As you say, the lighting is going to be too dynamic for a one-off on site WB to be useful.
But having an 18% grey swatch visible in every image I want to correct would solve that problem... Then I could just point the WB dropper in LR or PDCU at it to get my PP started with a decent and consistent WB reading.

I recognise (thanks to this thread) that the nature of LED lighting means that even if I get what appears to be a nice solid reading off an 18% grey tape or card, it may still not give me reliable enough colour information for WB correction, but I might get lucky sometimes.

I attended a gig recently where the band had a ring of grey(ish) taped labels around the base of all of their mics, and those labels worked OK as a target for my WB dropper. Hence my idea

QuoteOriginally posted by UnknownVT Quote
I shoot along side of pros all the time - for strong mono-colored lights a lot complain to the main act or promoter who talks to the lighting person -
Aha. So there are no 'pro' secrets to this, either in technique or hardware.

I often wondered if the big pro FF's like your Nikon D4's and D800's etc would do any better with their WB under LEDs than a mere K-x or K-5. Doesn't sound like they do.
09-15-2012, 11:11 AM   #169
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QuoteOriginally posted by rawr Quote
I often wondered if the big pro FF's like your Nikon D4's and D800's etc would do any better with their WB under LEDs than a mere K-x or K-5. Doesn't sound like they do.
Not that I know of -
it's dependent on the nature of the light (its spikiness would have low CRI = Color Rendering Index)
and possibly the Bayer matrix - as far as I know FF are still Bayer.

RAW would seem to have advantage - but because of the color spikes/imbalance - it doesn't
(see the number of "advice" to use RAW - then head over to the "challenge" starting at Post #103
where I posted the paired RAW/DNG+JPG of a strongly magenta lit scene,
see all the follow ups and tries/attempts to that -
and as far as I can see the "best" result to my eyes was the PDCU corrected JPG!
so as far as I am concerned I can mange reasonably well with JPGs

09-15-2012, 07:12 PM   #170
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filter?

just a thought would a yellow green filter help in this situ??
09-15-2012, 09:21 PM   #171
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QuoteOriginally posted by forestG Quote
just a thought would a yellow green filter help in this situ??
It might - but the main problem is that if there is only red and blue light then a yellow/green filter would theoretically filter out most of the light - or at least give a very dark scene/exposure.....

Of course the next shot the lights could change to white, or green

Last edited by UnknownVT; 09-15-2012 at 11:43 PM.
09-16-2012, 02:07 AM   #172
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My bit with PE 9 - 10 mins

09-16-2012, 07:26 AM   #173
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QuoteOriginally posted by dylansalt Quote
My bit with PE 9 - 10 mins
Thank you for doing this - did you work on the RAW or JPG?

(EDIT: I just re-did these literally as I was posting)
Original JPG shot (EXIF attached) -

(I have learned to save these with NO sub-sampling, so that the jpg does not destroy so much detail - please see posts: #155 & #156)

PDCU on JPG - processing = single click gray-point at coordinates 2192,872 -
then final adjustments in PhotoImpact 8 (very old version - free-with-magazine )
tone curves, contrast and sharpen (less than 2 minutes)


The originals are posted for anyone who cares to try some post-processing on these -

in Kx folder (link)
the paired DNG and JPG
IMGP4490.DNG
and
IMGP4490.JPG


Last edited by UnknownVT; 09-16-2012 at 10:44 PM.
09-16-2012, 09:18 AM   #174
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Some minor adjustments using the Quick Selection tool



I did auto convert the raw and brought into PE9
09-16-2012, 09:25 AM   #175
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QuoteOriginally posted by dylansalt Quote
Some minor adjustments using the Quick Selection tool
I did auto convert the raw and brought into PE9
Thanks again.
Did you use for your RAW conversion -
ACR (Adobe Camera RAW) from PS Elements
or
PDUC (Pentax Digital Camera Utility - the free s/w that comes with Pentax dSLRs)?

Thanks,
09-16-2012, 01:13 PM   #176
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QuoteOriginally posted by UnknownVT Quote
Thanks again.
Did you use for your RAW conversion -
ACR (Adobe Camera RAW) from PS Elements
or
PDUC (Pentax Digital Camera Utility - the free s/w that comes with Pentax dSLRs)?

Thanks,
ACR with PE9

I cover a ton of indoor climbing comps so have got so used to crap lighting and ISO 3200/6400.
09-16-2012, 09:41 PM   #177
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QuoteOriginally posted by dylansalt Quote
ACR with PE9.
Thank you for letting me know -
and for your efforts.
09-16-2012, 10:03 PM   #178
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I had a quick go at the test file with a few RAW convertors.

PDCU from the DNG


Capture One (C1) Express from DNG - this turned out well, with more detail.


Lightroom 4.1 from DNG - good detail and highlight retention, but tricky to clean up the magenta. Needs more work.


PDCU got the WB basics right quite quickly and it's optical corrections were nice. The other tools needed more work, but not too much. I quite like the C1 result.
09-16-2012, 10:26 PM   #179
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QuoteOriginally posted by rawr Quote
I had a quick go at the test file with a few RAW convertors.
PDCU got the WB basics right quite quickly and it's optical corrections were nice. The other tools needed more work, but not too much. I quite like the C1 result.
So do I -
you do realize you have just managed to deal quite successfully with a very severe color cast case
(the lighting did not have any green component, analyze the white T-shirt, or paper on the ground to confirm this, G=0 or 1)
- quite quickly at that.

Even though mono-colored wash lighting may still give you fits -
you do now know how to deal with them, quickly too -
you just demonstrated that to all of us .

Well done!
I hope you can now cope with what may initially appear to be a severe lighting problem, quite simply.
09-16-2012, 10:42 PM   #180
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QuoteOriginally posted by UnknownVT Quote
Well done! I hope you can now cope with what may initially appear to be a severe lighting problem, quite simply.
Thanks. It was an interesting exercise.

The big problem with this whole process is, however, doing it for a big batch of images, since stage lighting can be so dynamic. That hasn't proven to be much fun no matter what tool I use. If you have 50 images to correct, doing it one-by-one is too tedious.

In this regard I like how PDCU lets me, just with a right-click, copy and paste the correction settings from image to image. So where a sequence of shots share the same lighting, it lets me quickly apply the same WB and other corrections. I need to learn how to do this in LR and the other tools.
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