Infrared How To

What is Infrared? According to wikipedia.org
“Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of microwave radiation. The name means "below red" (from the Latin infra, "below"), red being the color of visible light of longest wavelength. "

How to take an Infrared Photo?

     In the film only days to capture infrared light, you needed special film sensitive only to infrared light.   However, now with DSLR's, it's much easier to achieve.    To test to see if your cameras sensor can pick up IR light try this: Take your TV remote and in a very dark room take a 30 second exposure of the remote while pressing the remote control button.   If you see any light comming from your remote control in the photo then your camera should be able to take Infrared photos.

     The way to take an Infrared photo with a DSLR is first to have a filter that allows only Infrared light to enter the camera.  The filter I use is the Hoya R72.  This filter only allows 720nm + of light to reach the film sensor, and blocks out all lower waves of visible light.  In this example the Hoya R72 filter was attached to a Canon 28-105mm lens on a Canon 10D DSLR body.  The first shot is a photo with out the Hoya R72 filter, the second shot is with the IR filter and the third shot is with the IR filter desaturated (converted to Black and White).

First shot specs:
Shooting Mode – Manual, Tv( Shutter Speed ) – 1/60, Av( Aperture Value ) – 16, Metering Mode – Partial, ISO Speed – 200, Lens – 28.0 – 105mm,  Focal Length – 105mm.

Photo copyright © 2005 John B.

Second shot specs:
Shooting Mode – Manual, Tv( Shutter Speed ) – 20, Av( Aperture Value ) – 16, Metering Mode – Partial, ISO Speed – 200, Lens – 28.0 – 105mm,  Focal Length – 105mm with Hoya R72 Infrared filter (same as first shot except for a longer shutter speed and IR filter).

Photo copyright © 2005 John B.


     Here is the second shot desaturated (color removed with software). Some cameras have the monochrome setting to which will yield similar results:

Photo copyright © 2005 John B.

How to focus for an Infrared Photo?

     To focus for an Infrared photo, I use the scale on the lens (if it has one).  I focus manually without the IR filter on, when focused, I place the IR filter on and adjust focus for IR light. With a DSLR you get a preview immediately, so you have an idea if you focused correctly. Here is an example of the IR focusing  scale on the Canon 28-105mm lens, the red numbers represent the new focus point in reference to the focal length:

Photo copyright © 2005 John B.

How to let in enough IR light for an Infrared Photo?

     Adjusting your camera to let enough Infrared light in to make the photograph will depend on your camera.  Most likely you cannot go by your camera's meter reading.  With my 10D I usually need much more light then what the camera meter tells me I need with the filter on.  At least with the digital cameras you can get a preview, and then make a decision of whether you need more or less light.

False Color IR

    I often hear questions on how to get Digital IR photos to be like Kodak Infrared false color film, so I decided to describe a easy way to give an IR photo some false color. Here is a photo taken with my 5D with a 17-40L with Hoya R72 IR filter on a cloudy day as it looks right from the camera.

First shot specs:
Shooting Mode – Manual, Tv( Shutter Speed ) – 25 seconds, Av( Aperture Value ) – 16, Metering Mode – Spot, ISO Speed – 100, Lens – 17-40mm f/4L,  Focal Length – 17mm.

Photo copyright © 2007 John B.

    Here is the same shot using software auto contrast setting. As you can see it tends to bring out other colors that weren’t in the original photo.

Photo copyright © 2007 John B.

    Of course you can always stick to Black and White like this, by just using desaturate in software or in camera select monochrome.

Photo copyright © 2007 John B.

False Color IR Example II

    Here is this example the photo was taken with a 5D and a EF 100-400L with the Hoya R72 IR filter.

Photo specs:
Shooting Mode – Manual, Tv( Shutter Speed ) – 10 seconds, Av( Aperture Value ) – 8.0, Metering Mode – Spot, ISO Speed – 200, Lens – 100-400mm,  Focal Length – 100mm.

Photo copyright © 2007 John B.

    Here is the same photo with adjustments to the green and blue contrast level setting with software (called Contrast Enhancement in Photo Paint, Contrast Levels in Photoshop, Tone Color adjustment in DPP). As you can see it tends to bring out other colors that weren’t in the original photo.

Photo copyright © 2007 John B.

     I still personally like regular color photos.   After all, I see in color not Infrared light with my natural eyes.  However, it is fun to see what other lights are around us, and can sometimes make quite a different photo aspect. 



Infrared How To

  1. jody b says:

    Thanks for your help and advise greatly appreciated . Jody B

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