Infrared Digital Photograph
Infrared photography is a form of photography where infrared light is used to capture an image; it should not be confused with infrared thermal imaging. In this article, we will explore the different types of infra-red cameras and their uses.
Infrared Photography: Infrared cameras are among the most versatile and useful cameras available - they help you see things in a whole new light! Here's how they work: Infrared light travels at a lower frequency (optical) then visible light, so it's typical to use some type of filter on your camera lenses to enable these wavelengths to pass through and reach your camera sensor. Such a filter helps capture the infrared light from an ambient source, or through an additional light source, which shows up in the resulting photo as "invisible" to the human eye that is reflected throughout the image - and results in a natural infra-red photograph. The resulting image shows objects in their true colors, with all of their thermal emissions revealed and captured in infrared photographs.
Infrared Camera Technologies: There are two main types of cameras used for infrared photography: dedicated (or monochromatic) cameras, and digital cameras. Depending on your needs you may want to consider each one for different purposes.
Monochromatic Infrared Cameras: Monochromatic cameras are special purpose cameras that only capture infrared light. They typically consist of a detector (such as CCD or FPA) with very little or no filtering to block out visible light - so they can be anything from a sophisticated, expensive, and professional grade camera to a simple gated camera (which is nothing more then an infrared-passing filter in front of a regular digital camera).
Digital Cameras for Infrared: These are the most commonly used cameras for all types of photographic imaging that fall under the umbrella term "infrared photography. The most basic of these is just a regular digital camera with an infrared filter installed in front of the lens. There are also IR-blocking filters for finding, panoramic stitching, and other accessories that can be purchased to supplement your camera. Another type of digital camera is the monochromatic (a camera with an infrared filter installed). Monochromatic cameras have very little light gathering capability - so their sensors are very likely to suffer from shadows or glare. This issue is mitigated by using optical zoom lenses which can have a variable focus point that adapts the exposure to compensate for the lack of exposure caused by infra-red light.
Infrared Flash Photography: An infra-red flash is a regular flash that is used in conjunction with an infrared camera, and not just for the human eye to see. The camera will capture the light from this flash' as "invisible", but each emitter will produce a different color based on its intensity - so you get an image that looks like you've captured it with a traditional flash, but with colors reversed. This technique can be used in macro photography or even wide angle (for sunsets and sunrises). An example of this technique is shown in the image below, which was photographed with a regular flash and an infra-red camera.
Infrared Photography Uses: Infrared photography can be used for artistic, scientific, medical and forensic purposes.
Monochromatic Infrared Cameras: Monochromatic infrared cameras are widely used in many research fields to identify chemical compounds by their spectral fingerprint. These types of cameras are also used in law enforcement, for security or wildlife observations. Monochromatic infrared cameras are typically used with a tripod and the shutter speed is only capture one image in an exposure, but it can be a very long exposure.
Digital Infrared Cameras: Digital infra-red cameras are most commonly used to visualize heat patterns, whether they be emitted by animals, machinery (such as an internal combustion engine), or even the heat from living matter (such as a patient's face). These cameras are also used for security purposes to detect areas of warmth in a room. In addition to imaging for forensic purposes, these cameras can be used for artistic purposes as well.
Infrared Photography Tips: Use a tripod to eliminate vibration. Make sure you don't have any bright lights in your image - especially sunlight. To capture just an object, use an infra-red filter and take a picture of it. Then you can add it to any picture, or remove it from the original image. If you notice that the filter on your camera is not transparent enough, try to take off the filter and wrap it with Saran Wrap (plastic wrap). The wrap will help block any reflections from nearby objects.
In addition to just regular photographs, infrared photographs can be used in conjunction with other forms of imaging such as thermal photography, night vision photography, line scans, or even in multiple exposure photographs.
Infra-red photography can be used to create some incredible images. Take a look at the following samples, created by infrared photography expert Marcelo Dias from Brazil.
Special effects have been added to many movies often with infrared film or infrared lighting. For example, in the movie "The Shining" (1980), there is an infrared shot of Jack Nicholson peering into a window. Also, in "The Terminator" films, the T-800 model has its eyes glow for an extended period of time during electrical power surges. This is accomplished by using infrared filtration techniques.
In the 1986 "Back to the Future Part III" Doc Brown explains to Marty that when he gets a new phone number, it shows as orange on his old one. The film was shot with infrared film (5600T) so that the phone numbers show up in orange even though they are universal yellow and black for old carrier phones.
The movie "Arrival", directed by Denis Villeneuve, has an extended scene in which a physicist named Ted Fersko uses an infrared camera to photograph a giant rock floating outside space as seen from Earth.
The Sega Genesis video game "Terminator 2: Judgment Day" (1991) uses a monochromatic infrared camera.
The movie "Fire in The Sky" (1993) uses an infrared lens as the main character held it up to his eye. The footage he got was mounted on a video monitor so that everyone around could see it.
In the movie "Maverick" (1994), the infrared portion of Maverick's scanner was used for seeing through a glass window, but not walls or other obstructions. He also had an ultraviolet mode.
Conclusion
An infrared device is used to see infrared light. Originally it was used for photography, but the infrared light can be seen by the naked eye as well. It can also be used for heat sensing, or night vision.
Infrared photography has a wide variety of uses in different fields, from the military, to medical research, and even law enforcement. Most of the time these images are created by regular cameras and lenses because the human eye is not able to see enough of the spectrum to capture all that exists in infra-red light. Infrared photography is also used for artistic reasons, allowing one to focus on color and detail instead of just black and white.