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Old Feb 18, 2007, 3:05 AM   #1
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Finally had the chance to shoot some digital IR last week with a couple of friends. Except for some hot spots in some of my shots, overall I'm satisfied. Would appreciate any and all suggestions in preparation for our next IR outing.

Thanks!






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Old Feb 18, 2007, 8:47 AM   #2
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Hi Donm,



Please forgive my lack of knowledge but how do you do IR pictures? Do you simply use an IR filter? Can you point to any useful references on this subject? It looks interesting.



Thanks,



--FrankD
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Old Feb 18, 2007, 7:41 PM   #3
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Hi FrankD,

There are a lot of resources on the web - tips from how to shoot up to how to process your shots.

For these shots I used the following:

1. 50mm 1.7

2. Cokin 89B filter equivalent - I'm using the A size holders

3. Tripod - since you'll be shooting for more than a second, you'll need this

I had my 5D set on manual focus and manual exposure. Before shooting, I set my custom white balance on a nice patch of green grass. Then I compose first without the 89B filter on. I do a test shot at f16 starting exposures from 1 second to 6 seconds. Since I shot on a sunny day, I had a bit of trouble looking at my camera's LCD to preview my shots. What I used instead was the histogram which was much easier to read in the daylight. I just made sure that my histogram's display was somewhere in the middle. If not, I just adjusted my exposure times accordingly.

For most of my shots that day, I stuck to f16 for my aperture. Exposure times varied from 3.2 seconds to 4 seconds. Most guys I've talked to are amazed by my exposure times. Most of them use Canons and can't get decent exposures unless they go beyond 10 seconds.

For my post processing, I based my PP from this site I found --> http://www.jason-nemeth.com/gallery2...ared/workflow/
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Old Feb 18, 2007, 7:45 PM   #4
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I was just reviewing my first post and noticed that my photos were bad examples for the hot spot I was complaining about.

Here's a better one:



If you'll look closely at the middle, you'll even see the octagonal shape of the 50mm 1.7 shutters.

-Don
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Old Feb 18, 2007, 8:53 PM   #5
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Donm,

Thank you very much for th info. I'm going to have to give this a try.

--FrankD
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Old Feb 19, 2007, 12:44 AM   #6
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Great IR shots. How did you get the sky so blue? Post Processing?

Rainer
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Old Feb 19, 2007, 1:02 AM   #7
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Thanks RDUVE. I did somepost processingon the photos. For the skies, I used the CHANNEL-MIXER, swapping the RED and BLUE channels - RED CHANNEL = 100%BLUE and the BLUE CHANNEL = 100% RED.

But I think the key here is the initial setting of the CWB on the 5D. I probably won't get the same blue skies if I set my CWB on something other than a patch of green grass.

Which reminds me, one of the things I need to remember to bring the next time I go on an IR outing is a nice large piece of green felt paper. I'll be using the felt paper to set my CWB on using the existing light conditions of where I'm shooting at.

Thanks!

-Don
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Old Feb 19, 2007, 11:32 AM   #8
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Interesting, I need to learn IR techniques from scratch. Just did a few test shots after I got my filter, but I never experimented with CWB. You are saying one should use a green background to set the Custom White Balance?

Rainer
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Old Feb 19, 2007, 12:05 PM   #9
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Try this free hot pixel remover:

http://www.mediachance.com/digicam/hotpixels.htm

I attached one that I copied from your post and ran it through the program.
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Old Feb 19, 2007, 8:41 PM   #10
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Hi Rainier,

There are actually several schools of thought as to what to set the CWB against when doing IR:

1. CWB set on white object with IR filter on

2. CWB set on green object with IR filter on

3. CWB set on green object without IR filter

I've never had luch with 1 and 2 above. For all my shots, I did #3, setting my CWB against the green grass at the cemetery.

Here's one of my shots before any post-processing work:



-Don
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