Techniques

Infrared Photography

by Deborah Sandidge | September 14, 2010

© Deborah SandidgePhotographers from the novice to the professional can photograph in infrared. Infrared light surrounds you—you just can’t see it. However, when you use a special filter with your digital camera, it becomes capable of recording infrared light. You can learn to envision the behavior and effects of infrared light, and see it in your mind’s eye. The camera can capture this invisible light to transform ordinary landscapes into something magical and ethereal. You can see how incredibly beautiful the world is in this different light.

Like sound, light travels in waves. When its wavelength is measured in nanometers (nm) or billionths of a meter, the light you typically see ranges only from around 400nm (the color violet) to around 700nm (the color red). This narrow band, also known as the visible spectrum, enables you to see violet, blue, green, yellow, orange, and red colors, and all their combinations.

Light at wavelengths shorter than those for the color violet is aptly named ultraviolet (UV) light. Most UV light is invisible to the human eye. The infrared spectrum begins at the other end of your range of sight, at wavelengths longer than those for the color red. The range of light from around 700nm to 1,000nm is referred to as near infrared because it is near the visible spectrum. Digital cameras can record light in this range with an infrared filter in place. The sun emits infrared light including UV and visible light. You can create exquisite photographs using infrared light from the sun, but light from sources such as candles or incandescent bulbs can also be recorded with infrared photography. In other words, you can creatively photograph infrared light at night.

Barn © Deborah Sandidge

Capturing Infrared Light

How do you capture something you can’t see with your own eyes? There are several methods that enable you to shoot in infrared. You can place an infrared filter on the lens of the camera (available at camera stores or online stores such as B&H Photovideo or Adorama), or you can have a digital camera converted to photograph in infrared. This means modifying your digital camera by removing the hot mirror located over the camera sensor, and replacing it with a filter that allows infrared light to pass through to the camera sensor. The former requires long exposure times (a tripod is necessary) and the camera may not autofocus properly. The latter is more expensive, but the camera operates normally with the major exception being that you can no longer use it to capture traditional color imagery. The difference in cost may be well worth the investment considering the cost of a premium 77mm infrared filter.

In either case, both methods allow the camera to record infrared light that is allowed to pass through the lens to the camera’s sensor. With an infrared-converted camera, the filter that blocks infrared light is removed and replaced with an infrared filter that blocks nearly all light except for infrared.

Using an infrared filter on or inside the camera allows infrared light to reach the camera sensor but blocks most visible and UV light. The camera can now record infrared light and you can create stunning photographs in infrared. A whole new world of creativity lies before you. When the natural color is removed from the scene, some of the reality is removed, and when some of the reality is removed, your pictures become more surreal and artistic. From a photographic perspective, the world is captivating in an entirely new way.

Many subjects reflect or absorb infrared differently than they do visible light. In an infrared image, the contrast range between the sky and clouds is often quite wide. The sky and bodies of water can appear very dark. Foliage appears white and is unexpectedly different and beautiful.

Skin tones take on an ethereal appearance that is very attractive for wedding photographers and for fine art nude photography. Infrared photography can look similar to timeless black-and-white photography, yet there is something enchantingly unique about it.

When some people think of infrared, thermal imaging (the capture of recorded temperature patterns) comes to mind. A common misconception about digital infrared photography, or even infrared film, is that it records heat patterns or thermal energies. With an infrared filter, digital cameras capture light in the near infrared range, recording how light is reflected and absorbed by various surfaces, not the actual temperature of the surfaces.

The much-coveted halation effect that is typically associated with capturing infrared images using Kodak high-speed infrared film (HIE) causes a visible aura around the very light areas in a photograph. This is explained by the lack of an anti-halation layer on that specific type of infrared film, and is not the outcome of infrared light, body heat, or thermal energy.

Thermal imaging sensors, on the other hand, register infrared energy emitted by subjects in the mid and far-infrared ranges. This is in comparison to digital cameras recording near infrared light that is reflected from subjects. Two interesting applications for thermal imaging processors are night vision for the military, and enhanced vision systems in ultra-sophisticated business jet avionics that employ the use of mid and far infrared light.

Cherry tree © Deborah Sandidge

Infrared Filters

You can choose from several types of infrared filters. A numeric system called Wratten is used to identify infrared filters and can be a bit daunting, especially when combined with many filter manufacturers’ own proprietary numbering systems. The simplest way to understand how an infrared filter functions is to look at the filter number. The higher the number, the smaller the amount of visible light that reaches the camera sensor.

For example, a filter labeled R72 means that the cutoff point for visible light is 720nm. This filter may also be called a Wratten 89B. This is often referred to as a “standard” type infrared filter. With this filter, a small amount of visible light reaches the sensor which is sometimes used for “channel swapping” to create the blue sky effect.

If you choose a filter such as the 87C (830nm), the cutoff point for visible light is higher, producing an image that has more contrast in infrared, the brightest foliage, and very black/white infrared images. Singh-Ray produces an infrared filter called the I-Ray, which blocks most visible light.

Each filter is very dark red, almost black. When you use an infrared filter in front of the camera lens, exposure times are longer because the hot mirror is in place and doing its job to block infrared light. Once you attach the infrared filter to the lens, it is so dark that seeing through it is impossible. You’ll need a tripod for the long exposure, and a cable release or self-timer to prevent transferring any vibration or movement to the camera. This unfortunately prohibits spontaneous, candid infrared photography that can be achieved with a converted camera.

The filter you choose depends on your desired outcome and budget. I used a Hoya R72 filter until I had my camera converted to photograph in infrared. The filter is easy to use and provides great results with my older model camera. However using this filter on some of the newer model cameras is more challenging, as they are designed to block infrared light much better than the older models.

There are a couple of factors to consider before purchasing a filter or having your camera converted. If you are just starting out, you may want to see the effect of infrared photography before jumping in and having a camera converted. The lens you use most frequently will determine the size of the filter, and in turn, the cost. If you purchase a filter to fit a 77mm lens, it can be quite expensive and the incremental difference in cost might be better put toward converting a camera. If you use a filter on the lens of a compact camera, you may find that the camera’s lens lacks a lens thread. It may be a bit of a challenge figuring out an adaptor system to allow for the use of an infrared filter.

You can purchase infrared filters online from companies such as B&H Photo, Adorama, Singh-Ray and LDP Net.

Pastel © Deborah Sandidge

Infrared Converted Cameras

Quick and candid infrared photographs are best accomplished with a converted camera. The camera functions just like an ordinary camera with similar exposure times but without slow shutter speeds that require setting up a tripod.

If you have decided that you want to be more spontaneous and tripod-free, then camera conversion is the choice for you. There are several companies (Life Pixel, LDP Net, among others) that will convert either your digital SLR camera or your compact camera, or both.

Another benefit to a converted dSLR is that you can use your favorite lenses, and you don’t have to purchase a filter for each lens. Note that you may need to manually focus for different lenses. Life Pixel provides a standard lens calibration, or you can choose a specific lens to be calibrated to autofocus in infrared. An infrared filter is now inside the camera and you can hand-hold the camera for infrared photography. There is a huge advantage being able to look through the camera viewfinder and easily see and compose your subjects. A tripod isn’t necessary unless you intend to use longer exposures—the same as color photography.

If you have a digital camera that you’re no longer using (perhaps you upgraded to the latest and greatest model as the older camera no longer suits your needs) this is the perfect opportunity to convert your old camera to an infrared camera.

It is possible to convert your own camera, but it requires a measure of comfort in disassembling and reassembling sensitive electronic camera parts as well as a steady hand—not to mention a dust-free environment. If the engineer in you wants to attempt it, tutorials and resources are available online. You can purchase infrared filters to use inside the camera through Life Pixel.

Life Pixel converts a wide variety of digital cameras using various conversion methods, ranging from black-and-white infrared, the standard filter, enhanced color infrared or the latest super color infrared filter. Life Pixel also adjusts the focus for certain Canon or Nikon lenses so that autofocus can be used. Or, a custom calibration is available for a specific lens of your choice.

LDP Net has a wide range of services and products, including infrared camera conversion and infrared filters you can use on the front of the lens. LDP Net also offers a wide variety of ready-to-use dSLR bodies and compact cameras already converted to infrared.

There are several choices for infrared camera conversion—which makes infrared photography very exciting! Let’s go into a little more detail about the differences between filter choices.

The deep black and white infrared filter (830nm) allows the least amount of visible light to reach the sensor, and creates black-and-white infrared images with good contrast. Very little Photoshop is needed.

Barn in field © Deborah Sandidge

The standard R72 type filter, (720nm) is the most common and is easy to work with. A small amount of visible light reaches the camera sensor, which can be used creatively for the desirable blue-sky effect.

The enhanced color filter (665nm) allows more visible light to reach the camera sensor and creates an image that is very detailed and has many options for creative color use. The tradeoff may be noticeable on cloudy days where the foliage appears less white than with the 87C (830nm) when converting images to black and white. However, contrast adjustments can be made to create an image with good tonality.

The new super color infrared filter (590nm) allows the most visible light to reach the camera sensor. This filter can create stunning imagery with a vivid blue sky and rich gold foliage. Like the enhanced color filter, a little more Photoshop is required for post processing, allowing the photographer to work with the more creative and artistic aspects of infrared photography.

All of the infrared conversion methods can be used for creating timeless and traditional black and white infrared imagery. The last two filters give the photographer more latitude with interpretation of color in infrared.

Photographing in infrared can give you a new outlet for artistic expression by allowing you to shoot traditional subjects in novel and interesting ways. A color photograph converted to black and white is quite different from a black and white infrared image. Nothing can quite compare with the surreal factor of bright white foliage, a dark sky and the uniqueness of how infrared light is reflected and absorbed by different surfaces. Infrared photography is a wonderful way to broaden your photographic horizons and expand your creativity!

Digital Infrared Photography (Photo Workshop) by Deborah Sandidge

Digital Infrared Photography (Photo Workshop)
by Deborah Sandidge

Available now on Amazon.com!

About the Author

Photography has been part of award-winning professional photographer, Deborah Sandidge's life since she picked up her first camera - it has evolved into her passion.

Deborah is the author of Digital Infrared Photography published by Wiley. She is an instructor at BetterPhoto.com and shares her knowledge and enthusiasm with photographers in her online classes.

Deborah's favorite photography subjects include Florida's birds and other wildlife, as well as its landscapes. Her travels, however, have not been limited to Florida's fascinating beauty; they have taken her from coast to coast of America and beyond to yield photography that stretches the imagination. She has had the joy and privilege of photographing areas ranging from Namibia, Africa, with its stunning dunes, and sweeping coastlines, to the cities and towns of Europe with its rich culture, history and majestic landscapes. Recently, the captivating architecture and beautiful people of Cuba captured her heart.

Deborah's passion is not only capturing images of people, places, and things with her digital cameras, but also in the creative work she does in the digital darkroom. She considers Photoshop her "artist's palette."

Check out Deb's blog, web site, and Twitter pages.

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