Infrared Photography: Filters, Camera Setup and Processing

Infrared photography records light beyond the visible red part of the spectrum. In creative photography, the usual approach is near-infrared capture: foliage, sky, water and other materials can appear very different from the way we see them. The result may be monochrome or processed into false colour.

This is different from thermal imaging. A conventional camera adapted for near-infrared photography generally records reflected light; it does not become a camera for measuring body temperature, diagnosing illness or seeing heat through walls. Understanding that distinction is the first step to choosing a workable setup.

Why infrared scenes look different

Materials reflect and absorb near-infrared light differently from visible light. Healthy foliage often appears bright, while skies can become relatively dark. The exact appearance depends on the subject, lighting, filter and processing.

A white-looking tree in an infrared photograph is not necessarily covered in frost. False-colour results are also interpretations of the recorded information rather than the colours a person would see. Use those differences to create a composition, while explaining the technique when the appearance could be misunderstood.

Distinguish an IR-pass filter from an IR-cut filter

An infrared-pass filter blocks much of the visible light while allowing a selected range of infrared through. An infrared-cut filter does the opposite: it suppresses infrared to support ordinary visible-light imaging. The label ‘IR filter’ can be ambiguous, so read the specification.

Most ordinary digital cameras include substantial infrared blocking in their sensor filter assembly. Adding an external IR-pass filter does not remove that internal barrier. Some combinations can still record useful infrared with long exposures; others are much less practical.

Choose between an external filter and a conversion

An external filter can offer a way to experiment with a suitable unmodified camera, often with a tripod and a longer exposure. Suitability varies by camera, lens and filter, so look for reliable information about the actual combination.

A professionally converted camera changes the sensor filter arrangement. An IR-only conversion and a full-spectrum conversion have different implications: the latter generally needs appropriate external filtration for the intended use. Confirm the configuration and focusing method with the conversion provider.

Nikon’s infrared photography feature illustrates external-filter and converted-camera approaches.

Conversion is a specialist modification, rather than simply removing a screw-on lens filter. Before committing a camera, understand how its normal photography use, focus and service arrangements will be affected.

Compare filter specifications rather than colour effects alone

Filters with different cutoffs admit different mixtures of visible and infrared light. A commonly used 720 nm filter can support strong monochrome work, while other choices may provide more false-colour options. The result also depends on the camera and processing.

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When choosing an infrared-pass filter, check its transmission specification, thread size and suitability for your camera.

Do not assume that a filter alone guarantees a particular blue sky or white foliage. A sample photograph may include a converted camera, custom white balance and substantial colour processing that your current setup does not reproduce.

Test exposure and focus on a still scene

Begin with a scene that includes foliage, sky and a stable foreground. Use a secure support if the exposure becomes long. Make several test photographs, checking the histogram and important detail rather than judging from an unfamiliar red preview alone.

Focus behaviour can differ from visible-light photography. Use the method recommended for your camera and conversion, and inspect the actual infrared image at a larger size. Do not assume that ordinary viewfinder autofocus or a generic lens mark gives the right correction for every setup.

A TV remote test can suggest that a camera detects some infrared, but it is not a conclusive compatibility test. Remotes differ and the exposure may hide a weak signal. Photographing the intended scene with a supported setup provides more useful information.

Check the lens for infrared hot spots

Some lenses create a bright or discoloured central area in infrared photographs. The effect can change with aperture, focal length and camera combination. A lens that performs well in visible light is not automatically a strong infrared lens.

Life Pixel’s infrared lens considerations explain this issue.

Test a fairly even scene at several apertures and inspect the centre as well as the corners. A hot spot that is difficult to correct consistently may justify using a different lens rather than repeating extensive retouching.

Use white balance and processing deliberately

Infrared previews can look strongly red or pink because of the camera’s colour processing. This is not evidence that the photograph records a higher physical temperature. A custom white balance or suitable RAW workflow can make the information easier to work with.

Compare the transmission specification of this infrared filter with your intended effect. A different wavelength cutoff can change both the appearance and the exposure required.

RAW processing software can have limits when neutralising infrared colour casts. Follow guidance for your particular files and consider a suitable profile or converter when ordinary white-balance sliders do not provide the needed range. There is no universal temperature and tint setting.

Choose monochrome or false colour for the image

For monochrome, concentrate on the brightness relationships, texture and separation between foliage and sky. Avoid pushing contrast until bright leaves lose detail. A colour-channel swap can be part of a false-colour workflow, but it is a creative choice rather than a required correction.

Life Pixel’s infrared getting-started guide discusses white balance and RAW processing.

Keep the original file and compare versions. Processing should support the composition rather than substitute for one. Inspect edges, colour transitions and central hot spots before exporting.

Build a repeatable first project

Return to one accessible scene and compare how the infrared result changes with lighting and composition. A shorter exposure may retain moving leaves more clearly; a longer exposure may deliberately blur water or clouds.

Before buying an infrared filter, confirm its thread size and camera compatibility. The lens and sensor response also influence the result.

Record the camera configuration, filter, lens and exposure settings with your results. Change one variable at a time. That method makes it easier to understand which unusual appearances came from the scene, equipment or processing.