easy infrared photography with filters

What you get with this tutorial: Interesting colour and infrared effects

true colour
infrared

What you need: A digital camera with sensitivity to infrared light; a tripod; cable release or shutter delay; an infrared filter

Some digital camera sensors are sensitive to infrared light (this is not the same as heat sensitive cameras though). They contain filters in from of the sensor to reduce the infrared sensitivity, but some cameras are still able to take usable infrared photos.

How to test if your camera will detect infrared

In a darkish room point a remote control into the camera lens, press one of the buttons and see if you can see it on the preview screen or in a photo. Just because this works, it does not mean you will get decent infrared photos, but it will give you an idea if there is any point trying to pursue this technique.

If your camera shows the glow from the infrared diode then it might be worth buying a proper infrared filter. I have had three infrared filters. My first was a 77mm Kood R72. I also had a Cokin slot-in infrared filter, but I managed to crack it. As I no longer have the lens for the 77mm filters, I have recently invested in the smaller filters to fit the standard lens, so I now have a 58mm GreenL IR720 filter, bought for the grand total of £10 from eBay. All these filters give similar results, so I have no hesitation in recommending the cheap eBay filters for general use. These are proper infrared filters. If you look at them, you can hardly see through them, so there is no chance of seeing through them with a standard DSLR for composing your photo, you will have to screw the filter on after you set up your composition. My pocket Lumix will show a live view with the infrared filter on, so cameras that use live view might be more successful.

Let’s do it!

Your filter has arrived from China, so let’s take our first infrared shot. Things to explore: foliage (which will look white), clear skies (which will look almost black). Dramatic scenes of buildings in the landscape are very effective as well.

Set up your camera on the tripod and compose your scene. Now, being careful not to move the camera too much, place the infrared filter on the lens.

Camera Settings

If you can, set your camera to take photos in RAW or DNG format, rather than JPEG. It doesn’t make a huge difference on my Pentax DSLR, but the Raw format gives you greater control when you get back to your computer to edit the photo. If your camera only shoots JPEG, set the white balance with the infrared filter attached. This is outlined in the compact camera infrared tips page.

Focus

Check and see if your camera will focus, it is work noting that infrared is in focus when the lens is slightly short of the actual distance. Some lenses include a red indicator mark on the focus scale to help, otherwise you may have to experiment a little. The two lenses I do have that have this red indicator show an infrared infinity focus at about 10-15 metres.

Taking the photo

The exposure for your infrared photo is likely to be in seconds, so the steady tripod and the remote shutter release are essential. If you do not have a remote release, try using the 2 second delay.

Exposure

too dark
2 stops exposure compensation

After you take your image, check the histogram on the screen. This is useful, as the camera metering is not likely to be too accurate for infrared. Your photo is likely to be too dark (all the levels off to the left of the histogram like the image on the left) so add some exposure compensation. The image will also be completely red, but we will try to adjust for that later.

Once you have a few photos using this technique, it is time to see what you can make of the images. Copy them over to your computer and fire up your favourite image editing software. For this tutorial we are using Google Picasa, which is as good as anything for simple editing.

Here is a quick work flow to try:

raw image from the camera
spot white balance from the grass

Adjust the white balance of your photo using the spot white balance feature (Neutral Color Picker on the tuning tab in picasa).  We know that foliage is supposed to be white in infrared, so use an area of grass or leaves as a reference.

auto levels

Auto adjust the contrast on the Basic Fixes tab (or auto level in other software)

converted to black and white

The images that I get this way have a warm sepia type effect, but you might prefer the drama of black and white.

Things to be aware of:

Some lenses produce a ‘hot spot’ on infrared photos, this usually looks like a circular light patch in the centre of the photo. This seems to be more apparent with the proper IR filters and might be a reflection between the back of the filter and the lens. Some lenses are more susceptible than others, all my Pentax lenses I have seem to avoid this problem, the Samsung 12-24 I used to have sometimes produced this effect.

As the exposures are longer than normal, you might suffer from more grain and noise in your photos. This is especially true if your photos are underexposed. Check the camera exposure histogram and adjust as needed as you take photos. I usually end up adding around 2 stops of exposure compensation (ie an exposure 4 times as long as the meter says).

Other things to try

merged true colour and infrared photo

You can create some interesting effects by combining an infrared with a normal photo. If you photo software will support layers, try combining them as layers and changing the opacity of the top layer. The hard light layer effects can be very interesting as well. For picasa, you can still combine images. Select the two images you want to use. Click on the collage button, then choose the ‘multiple exposure’ collage type rather than the traditional arrangement of separate images.

Other filters

There are other ways of creating your own infrared filter as well. You could try using a 35mm slide that has been processed but not exposed to light, or you could try the disk film from an old floppy disk drive. Both of these will filter out visible light, but neither are very big, and the results I have had with these were not very clear, so for £10 I would buy a filter if you want to try this out.