Digital InfraRed Photography

Summer at the Lakes II

I recently bought an Infrared filter for my new Canon 40D in order to try out some non-visible light photography. In this first article I will attempt to explain how to capture IR shots and then in the next post we’ll look at processing methods.


The filter I bought is by Kood and is an R72 circular screw in type filter. There are various sizes - I bought a 77mm one for my Sigma 10-20mm. The Kood is a cheaper variant of the popular Hoya R72 filter.

IR Filter

The filter is a very dark navy blue in colour and through it you can see exactly nothing!! The downside to the screw in type is that it is difficult to compose a shot with the filter on. You either have to remove the filter, compose and then put it on, or use a similar technique to night photography - Shoot a few high ISO, max aperture shots first and then stop down for the final shot.

Shooting for B&W

B&W infrared works really well for some subjects and also where there is no variety in the amount of reflected infrared light. Foliage reflects more infrared than the sky, buildings e.t.c. Black and white processing works really well for architectural objects.

Black Sea Skiff Chepstow Castle from the River WyeWindy Bay

The shot on the far left was taken at about 7pm with a bright summer sun shiny behind me. The water doesn’t reflect much infrared light so came out a lovely deep black. The structures have very bold contrasts too, which make the buildings stand out.

White Balance setup for False Colour

For producing colour Infrared shots the most important factor to get right is the white balance. There are various ways to achieve this in post production although none are as good as taking a shot and using that to set the custom white balance of the camera. To do this, set the camera to Auto White Balance and take a shot of a patch of grass. Defocus the lens so you don’t get too much visible grass and make sure the grass fills the frame without any shadow from you or the camera.

WhiteBalance

WhiteBalanceHisto

The first shot shows a white balance frame and the second shows the histogram data from the back of the camera. Note that the RED channel contains more information that the BLUE and GREEN channels and also at a different part of the spectrum. The white balance frame is the key - You can try clipping the red channel, like I have done here - which will render the foliage very white on the final exposure and also help with the relative levels of BLUE and GREEN in the final shot - which are quite important. I have also tried shots where the RED channel was no clipped and all the channel information was contained within the histogram limits. Experimentation is the key!!

Once you have a shot, set it as the custom white balance in the camera menus. Top tip! Keep a spare memory card with some differing white balance setups and you can try them whilst out on the shoot!

SetWhiteBalance

Taking Test Shots

Next up! Shooting.

Manual is best, every time. The way to approach an IR shot is to use the techniques for shooting at night. Start at a very high ISO and wide open aperture, get a decent composed and exposed image and then stop down the ISO and multiply the exposure time up to fit.
Remember a halving of ISO doubles the exposure time, as does moving a stop down in aperture!

I have found that a reasonable starting point for IR on my unmodified Canon 40D with a Kood R72 IR Filter is about 2 seconds @ f/5.6 at 3200 ISO on a bright summers day. For those without 3200 ISO the same would be 4 seconds @ f/5.6 at 1600 ISO. This is a great way to set up composition, check the effects of the white balance adjustment and to gauge a decent exposure. Here, try not to clip the histogram but more likely will be the temptation to not expose enough. Make sure the image reaches both sides of the histogram… Stay at f/5.6 and 3200 ISO but tweak the shutter speed up (or down) to get the exposure. Also its best to manual focus at infinity or between 1m and infinity. Your camera may be able to autofocus through the filter but you won’t be able to see exactly what it is focusing on (!) so its best to focus far and rely on hyperfocal distance to sort you out!

The Final Shot

Once you have the setup you think is best, stop down.. So for my initial conditions of 2 seconds @ f/5.6 at 3200 ISO, that would make 32 seconds at f/5.6 at ISO 200, which is roughly good enough to do 30 secs without getting the remote release out and going into bulb mode!!

From there its 64 secs @ f/5.6 for ISO 100, 128 secs @ f/8 for ISO 100, 256 secs @ f/11 for ISO 100… so it soon mounts up to over 4 mins, just to get a reasonable depth of field! For general landscapes you can get away with f/8, if focused on infinity.

Viewfinder Blocked

The last thing to do is watch out for the light! I usually go for a subject that has light on it with the sun behind me. This can create problems with the exposure, as visible light can get in to the camera via the viewfinder, especially if the sun is behind you.. Canon provide a viewfinder blocker on the camera strap, just remove the eyepiece and use the cover on the strap to block the viewfinder. It definitely makes a big difference to the long exposures.

Summer at the Lakes I Wye Valley Infrared St Marys Church

Next Time..

Processing stuff! Black and white and False colour tips that I’ve found so far! Enjoy!

8 Responses to “Digital InfraRed Photography”


  1. 1 Luke Raddy June 25, 2008 at 2:25 pm

    You are a little angel for your mega infra-red guide. Really nice stuff. Cheers Mr Steve.

  2. 2 jim June 25, 2008 at 6:25 pm

    hi,
    I was told that I would have to modify my 40D to take infrared photos, did you have to modify your 40d, or just attach the R72? It’s an intriguing effect, but I’m not up to modifying my camera, just yet. And also, from the various makers of this style filter, is one better than another, or basically equal? Thank you for the post, it was very informative. Cheers.

  3. 3 stevencastle June 25, 2008 at 7:01 pm

    @ Jim.

    My 40D is UNmodified - just with the R72. With a modified camera you drastically reduce the exposure times. Effectively with my camera and just the R72 I’m looking at at least 30secs @ ISO 200 and f/5.6. Luckily I just love long exposures and the effect of motion you get, so that’s fine with me!

    As far as filter goes, a friend of mine has the Cokin one, which is basically a P-Series one but is having terrible trouble with it. The Hoya R72 is generally well known but is expensive, twice as much as my Kood filter. The Kood is new to their filter line up and as far as I can see, works ok for me!

    @ Luke, Cheers M’Dears!

  4. 4 Kyle July 20, 2008 at 8:42 am

    You wouldn’t mind posting some pictures of the differences with the eyepiece cover on and off, would you? Or, you can send me some pics. That’d be AWESOME as well. :)

    kyle.kruchok@gmail.com

    Cheers!

  5. 5 stevencastle July 20, 2008 at 9:05 am

    Heh heh, I’d love to but I always delete em if I happen to forget… I’ll try and get one next time I’m out. Essentially you end up with all sorts of stage colour defects and hotspot areas - its not nice!

  6. 6 Jenn July 31, 2008 at 12:32 am

    So you’re still getting some ‘colore’d light then aren’t you?…shooting with an un-modified camera and only a filter on the lens…

    I have a Sigma and so can remove the sensor protector and shoot essentially with a modified camera and a lens (R72 filter.) I’ve tried applying your tips for false color and yes did a custom white balance setting on a full frame of unfocused, sunlit grass.

    My images did not come out anything like yours.

    Should I try leaving my camera ‘un-modified’ and just use the lens filter? If I modify and use a lens filter should I be planning on monochrome images?

    Thanks,
    Jenn

  7. 7 stevencastle July 31, 2008 at 6:09 am

    Hi Jenn, Thanks for stopping by.

    Since I don’t have an unmodded camera, my only answer is ‘I have no idea!’.

    From what I understand with the sensor filter removed the camera becomes more sensitive to IR so you can do the same kind of shots but without the ridiculously long exposures. You can even handhold at sensible apertures.

    But I have also seen the crazy coloured pics taken with modified cameras. The most popular place for info about modified camera is over at http://www.lifepixel.com/ . These guys do the modification and have tutorials and examples you might find helpful.

  8. 8 Jenn August 1, 2008 at 1:20 am

    Thanks. I’ll check out the link.

    I have not ever had crazy long exposures and have successfully handheld all my exposures…but I’ll do some more research and leave you an update if I can determine anything.

    Thanks again.

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