iSyndica

Laurent Dambies, microstock photographer and blogger at Microstock Experiment, is going to share with us in this tutorial his experience shooting infrared photography, or IR photography.

Infrared panoramic landscape of a japanese garden with a lake and bridge

How does it work?

Light is an electomagnetic radiation with visible light made of wavelengths in the 400-700 nm and infrared light in 700-1200 nm range (near-infrared). Longer wavelengths will fall in the range of mid-infrared and far-infrared. The latter is used in thermal imagery for example. An IR filter placed on top of the lens will block most of the visible light and lets near-infrared hit the CCD. Unfortunately, the IR sensitivity of a camera is lowered by a hot mirror placed on top of the CCD sensor which job it is to protect it.

Why infrared photography ?

Infrared photography gives a dramatic and surreal effect to pictures. Foliage and grass have the property to reflect infrared radiations and appear much brighter in IR giving off an ethereal white glow; in some pictures grass can even be mistaken for snow. Different foliages have different IR reflectance, and this can be further impacted by diseases or insect infestations. Blue sky and water will appear dark. Skin or shadows will yield interesting tones and nuance. Depending on the light, textures can be revealed in more details as well.

Challenges in IR photography

Focusing & Depth Of Field

Focusing in IR is different than in visible light so producing sharp images can be tricky. If you are lucky, your lens might have an IR focus mark on it. If not, the technique is to take several shots at different focus distances, preferably with a small aperture. Another technique, more universal, is to use the hyperfocal distance but once again you will have to experiment to find the proper distance.

Exposure

Because the IR filter is very dark, indications given by your camera cannot be trusted and most of the time exposures of several seconds are needed. I typically use 2 to 15 seconds exposure times with a tripod. On the positive side, long exposures can give you great visual effects with water and clouds for example.

Equipment

Your results will vary when you begin experimenting with IR photography. To a large extent, your results depend on the IR sensitivity of your CCD sensor as most manufacturers add an IR blocking filter, also called hot mirror, in front of the CCD. A second and obvious factor is the lens you use. Some lenses are known to cause flares or hotspots in the pictures.

My gear

I use a Canon Powershot G9 using a Hoya R72 filter on a 58 mm Lensmate lens adapter. To obtain longer exposures, I select the ND function on (3 stops) and/or put a ND4 filter (2 stops) on top of the R72. As its name suggests, the Hoya filter blocks wavelengths below 720 nm. The graph below taken from their site illustrates that (show for wavelengths 700 nm to 5000 nm).

Hoya R72 Transmittance (T) Curve

I then use the hyperfocal distance and follow mainly this tutorial on flickr called "Universal settings for IR-work with G9"

I shoot raw at 80 ISO to limit noise as much as possible.

Although quite expensive, a lot of digital cameras can be modified to remove the IR filter in front of the CCD. This then makes it possible to take handheld IR pictures.

10 steps workfow

I use Adobe Photoshop CS3 and Lightroom 2 for all my photo work and always start my workflow with RAW files. I do not usually go for B&W processing to maintain some blue sky.

In Lightroom 2:

1. Open the Raw file you wish to edit
2. Set the color temperature at 2000, tint -50
3. Remove the noise set Luminance 60
4. Adjust chromatic aberration : all edges
5. Export as jpeg or tiff

In Photoshop CS3:

6. Swap red and blue channels: red 0 blue 100, blue 0, red 100
7. Image--> adjustements levels blue and green
8. Image ---> curves define gray point
9. Import in Lightroom 2 to adjust hue/saturation on the different channels to get the desired results.
10. Export as jpeg

Microstock and IR photography

Although not popular, you can find IR pictures in most stock agencies’ collections. At the time of writing, a search on ''infrared landscape'' and ''infrared building'' returned 537 and 128 images on Dreamstime. Istockphoto is very picky about IR images: only 137 hits returned for ''infrared landscape'' and 45 for “infrared building”!

The most challenging element is to produce IR pictures that can be accepted as they tend to be noisier and less sharp. Downsizing from 12 to 5 MP can help.

Infrared picture of the Bell bridge and Armadillo SECC on the Clyde river in Glasgow

Check out Laurent's Dreamstime gallery for more of his infrared work

For further readings:

dpFWIW A lot of detailed informations and links about IR photography
Life Pixel Services and tips about converting your camera to infrared
Complete Guide to Digital Infrared Photography by Joe Furrace, Lark Books, 2006, 160p.