attack_donut
member
Reged: 16/12/2006
Posts: 135
Loc: East Coast
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So in the mail the other day came my Hoya R72 filter.
After having read around the web, everyone was saying to expect longer exposure times (and judging from the darkness of the glass, I was expecting this as well) but was surprised when it didn't take any longer to capture an image.
So, now I'm got this great (ha!) image, what the heck do I do with it? It's a very wine dark colour throughout. Fair enough, I also expected that, but I was expecting, I dunno, some IR image...where did I go wrong?
Samsung GX-1L aka Pentax *ist D
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Storms arise and eclipse the sun, the march of kings has begun.
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LargeFormat
old hand
Reged: 24/10/2006
Posts: 1059
Loc: Buckinghamshire and Cumbria
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Your camera has an infra red filter in front of the sensor. This stops infra red. You have put an R72 in front of the lens. This stops everything other than infra red. The consequence is that virtually no light is reaching the sensor. To do infra red phoptography you need to remove the camera's filter. Recent threads cover doing this yourself or getting it done for you.
Last week's AP reviewed two Fuji cameras dedicated to infra red photography.
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beejaybee
Marvin
Reged: 18/07/2007
Posts: 4444
Loc: Really Here In Name Only
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Quote:
After having read around the web, everyone was saying to expect longer exposure times (and judging from the darkness of the glass, I was expecting this as well) but was surprised when it didn't take any longer to capture an image.
So, now I'm got this great (ha!) image, what the heck do I do with it? It's a very wine dark colour throughout. Fair enough, I also expected that, but I was expecting, I dunno, some IR image...where did I go wrong?
The light meter doesn't react the same way as the sensor ... you're going to have to apply loads of exposure compensation or (more probably) manual mode with "guesstimated" metering. Start at about 2 stops over what the meter says and increase in 1/2 or 2/3 stop increments until the sensor starts to saturate, then back off a bit. Once you've found out what correction needs to be made, that will serve as a reasonable starting point in future. You may need less correction when the light is reddish anyway (dusk & dawn) and more when the light is bluer (midday sun, cloud, deep twilight etc).
Your image is red because only the red sensitive photosites on the sensor have any sensitivity at all to the IR transmitted by the filter. You will need to convert to monochrome; perhaps the camera's built in "monochrome picture style" conversion will do, but doing the conversion in external software (Photoshop) and setting the ratios to 100:0:0 R:G:B will almost certainly work better.
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El Sid
Going potty
Reged: 14/04/2003
Posts: 9296
Loc: Sussex-by-the-Sea
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Quote:
So, now I'm got this great (ha!) image, what the heck do I do with it? It's a very wine dark colour throughout. Fair enough, I also expected that, but I was expecting, I dunno, some IR image...where did I go wrong?
When you say wine dark I presume you mean an all-over deep-red to maroon colour with no real visible image? In which case you didn't use a long enough exposure.
Not sure how the Samsung meters but I'd be damned surprised if it set anything like a normal exposure time... 
This is my typical procedure with by Canon D30:
Set the ISO to at least 400 (in sunny weather - higher in duller conditions).
Set the camera to manual exposure mode.
With the filter removed I focus manually on the subject and note the focus distance.
Replace the filter and set the noted focus distance to the IR index on the lens scale - assuming the lens has a focus scale - which is usually a red mark to one side of the main focus mark (which side depends on focus rotation). When using a lens without an IR mark then I set a small aperture to ensure the subject remains in focus.
Set the desired aperture - usually at least f8-f11 with wide angle lenses maybe smaller with longer ones.
Guesstimate the shutter time... Generally I find something like 8-15 seconds is enough in sunny weather but a bit more if it's dull. It's very much a matter of trial and error. You will need a tripod of course...
Some folks like to set a custom white balance with the filter in place using grass as the balance colour. Personally I have yet to see any advantage in this - perhaps I'm doing it wrong...
Any way up you will end up with a pink/red image. This needs to be converted to black and white. If you google around the net you will find lots of different approaches. Personally I tend to use Canons own DPP RAW converter and play about with a variations of colour temperature, hue, contrast and exposure compensation to produce a mono image to export to PS for polishing up. Occasionally I may use my old copy of RAW Shooter to adjust the basic image but then I have to convert to mono in PS.
I strongly recommend using RAW format for IR as you will need to muck about with the images a lot...
Here's a couple of worthwhile sites to trawl through...
DPfwiw...
Wrotniaks Digital IR...
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Nigel
Completely BSRIPN 
ElSid Gallery
A camera in the hand is better than one in the cupboard........
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PhilW
Blue Peter Badge Winner
Reged: 14/03/2007
Posts: 921
Loc: Near Wakefield, Yorkshire
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Quote:
To do infra red phoptography you need to remove the camera's filter.
THIS IS NOT TRUE!!!!!
Removing the filter just allows you to take Digital pictures without the long exposure.
To the OP You need to shoot in manual mode - try 15sec at f4.5 ISO200 as a start and adjust after looking at the histogram.
The file you get from the camera should look something like this:
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Phil Winterbourne
http://www.pbase.com/calis
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attack_donut
member
Reged: 16/12/2006
Posts: 135
Loc: East Coast
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Hi gang-
I discovered the manual mode did improve things markedly. I'll have to try long exposure times, the ones I did were (handheld, my tripod is not at work) around 1.5 seconds, f/8 from a 90mm lens, and looked a little blown out.
I set a custom white balance, will try and experiment more.
Thanks gang to all who have helped and set me straight!
Cheers!
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Storms arise and eclipse the sun, the march of kings has begun.
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attack_donut
member
Reged: 16/12/2006
Posts: 135
Loc: East Coast
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I took some quick pics below. According to my camera, the shutter speed was 1/30. ISO 200 (lowest it will go), F/8.0 and moderately overcast. These are right from the camera, other than being resized, no other mods were done
Click to view - 150k
The next pic is 3 stops higher, 1/10, but all other settings are the same.
Click to view - 172k
Here is at 1/4 sec.
Click to view - 178k
and finally at 1 sec exposure
Click to view - 268k
Any suggestions at how far beyond the camera's suggestions I should go?
Moderators Note: All photos (including IR ones) have to be under 100k to be displayed on the forums, as in the Forum Rules. Your photos are all OVER 100k and have been changed to links. Please be more careful in future
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Storms arise and eclipse the sun, the march of kings has begun.
Edited by Fen (08/07/2008 20:01)
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PhilW
Blue Peter Badge Winner
Reged: 14/03/2007
Posts: 921
Loc: Near Wakefield, Yorkshire
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Those are getting there.
Why f8? I'd go s wide as you can (probably f4.5 if you are using a kit lens)
From the pics you have shared I'd say the in built IR filter is a lot weaker on the samsung than on my Canon 5D. as I also have a GX-10 I'll have a play...
As for the cameras suggestions - ignore them completely and just go with what seems to work.
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Phil Winterbourne
http://www.pbase.com/calis
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beejaybee
Marvin
Reged: 18/07/2007
Posts: 4444
Loc: Really Here In Name Only
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Quote:
Any suggestions at how far beyond the camera's suggestions I should go?
The last one (1 sec) looks a bit blown to me but the 1/4 sec isn't really exposed enough ... somewhere in between, then add a bit of contrast after converting to monochrome, I reckon. Other people may well have different opinions; there seems to be something of a fashion for blowing out the highlights with IR shots, which may be connected to the operation of the histogram on the preview screen when there is a signal only on the red channel.
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Dave_Cox
old'n'grumpy
Reged: 12/07/2006
Posts: 2884
Loc: somewhere in Sussex
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Taken with an unmodified DL2 and R72 filter, manual focus and auto exposure:
Exif data:
Camera: Pentax *ist DL2
Exposure: 0.167 sec (1/6)
Aperture: f/4.5
Focal Length: 24 mm
ISO Speed: 200
Exposure Bias: 0/10 EV
Flash: Flash did not fire
Converted to greyscale
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Growing old disgracefully..!
http://snapper56.deviantart.com/gallery/
http://www.flickr.com/photos/dave2006/
Edited by Dave_Cox (08/07/2008 21:56)
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attack_donut
member
Reged: 16/12/2006
Posts: 135
Loc: East Coast
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Sorry Mod-
I saw the bit about X by Y size limitations, missed the part on filke size limits.
One of the things I was curious about, when I was reading about IR, was the long exposure times, perhaps it's because the other cameras have heavy IR filters on the CCD, whereas mine doesn't.
Thanks for all the tips and tricks. Look forward to getting the hang of this and posting some nice pics in the future.
Cheers!
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Storms arise and eclipse the sun, the march of kings has begun.
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