The Light We Cannot See

Working With Infrared and Hidden-Spectrum Imaging

Most people who come into contact with infrared imaging do it through cheap phone attachments or modified cameras. I spent years dealing with IR photography and night-vision systems across a few different projects, and I keep coming back to the same issue: the hardware is easy to find, but getting clean results without spending weeks tweaking is the hard part. The phrase The Light We Cannot See keeps coming up in forums and discussions around this space, usually from people who want to get into near-infrared or thermal work and can't figure out where to actually start. There are guides out there, but most of them are either too basic or written by people who bought one camera and shot one subject once. What follows is the practical side of things.

Getting Started With Infrared Photography and Detection

First, you need to understand what wavelength range you are actually working in. Near-infrared sits roughly between 700 nanometers and 1400 nanometers. Thermal infrared is a whole different ballgame, starting around 8000 nanometers and going up. Most consumer IR photography stays in the near-IR band. That means you need a camera with the infrared filter removed or a dedicated IR conversion done on an old body. You also need lenses that transmit IR well. Some modern lenses have coatings that block near-IR light, and you will spend hours wondering why your converted camera is producing dark, useless frames before you figure out the lens is the problem. I ran into this exact situation a couple of years ago with a Nikon D700 conversion. Everything looked right on paper, but my test shots were consistently underexposed by about three stops compared to what the light meter was suggesting. The culprit was a Tokina 11-16mm f/2.0 that I had been using for years on the stock body. The coating on that lens blocked most of the IR spectrum. Swapping to an older Sigma 10-20mm fixed the issue immediately. Lenses matter more than cameras in this space.

Equipment You Actually Need

A converted camera is the foundation. Companies like moddedcameras.com, Lifetime Camera Repair, and IRShop.eu handle conversions for most major brands. Costs run anywhere from $300 to $900 depending on the camera body and whether you want a full-spectrum conversion or a dedicated 720nm pass filter installed. For most people starting out, a 720nm conversion is the sweet spot because it still produces images that look somewhat natural and is easier to work with in post. You will also need an IR pass filter for your lens. Since the camera no longer has an internal IR cut filter, putting a filter on the front of the lens is non-negotiable. A 720nm filter will block visible light and only let infrared through. These cost between $40 and $150 depending on the brand and size. Don't buy the cheapest ones you find. Cheap filters introduce color casts and softness that are nearly impossible to fix in post. A sturdy tripod is essential. At 720nm, exposure times typically run from one second to thirty seconds depending on lighting conditions. Handholding is not an option for anything but the brightest scenes. A remote shutter release or the camera's timer function will prevent shake during longer exposures.

The Shooting Process

Set your camera to manual mode. Autofocus will not work reliably with an IR filter on the front because the filter blocks the autofocus assist light path and changes the focal plane. Switch to manual focus and use live view at maximum zoom to confirm your focus point. This takes practice. If you are shooting foliage, focus on the mid-ground subjects rather than the closest leaves. ISO should stay low. I shoot at ISO 200 on most conversions. Higher ISO values introduce noise that becomes very apparent in the smooth sky areas that IR photography typically produces. Aperture depends on your depth of field needs, but f/8 to f/11 is a good starting range for landscape-style IR shots. Shutter speed is where you adjust for exposure. Use the histogram, not the LCD screen. The screen will lie to you because the sensor is seeing light your eyes cannot detect. Exposure compensation is tricky with IR. Metering systems are calibrated for visible light. When you point a camera at a green forest through a 720nm filter, the meter will try to underexpose the scene because IR-reflective foliage appears very bright. Take a reading from a gray card if you have one, or bracket your shots and check the histogram afterward. I usually bracket in +/- 1 EV increments and pick the best exposure in post.

Post-Processing Workflow

IR images come out of the camera looking dark, flat, and often magenta or green-tinted. This is normal. The raw file contains all the infrared data, and your job is to make it usable. Start by converting the RAW file in Adobe Camera RAW or Lightroom. Set the white balance to around 3200K to 4000K. This gives you a cooler base that you can work from. Adjust the exposure slider until the histogram shows a balanced distribution. Boost the contrast slightly. The key adjustment in IR post-processing is the channel mixer or color balance. In Photoshop, go to Image > Adjustments > Channel Mixer. Try swapping the red and green channels or reducing the red channel output. This is what creates the classic white-foliage IR look. You will need to experiment because every conversion and every lighting scenario behaves differently. If you are working in Affinity Photo or Capture One, the principles are the same but the tools have different names. The channel mixer in Capture One lives under the RGB tab. In Affinity Photo, use the Channels panel and adjust individual channel levels.

For more creative results, try split toning. Add a warm tone to the highlights and a cool tone to the shadows. This pushes the image away from realism and toward the ethereal quality that IR photography is known for. Spend about twenty to forty-five minutes per image on a typical edit. A well-edited IR photo is not a five-minute process.

Common Pitfalls

Hotspots are the most common problem. A hotspot is a bright circular area in the center or corner of your frame caused by internal reflections within the lens. Older vintage lenses from the 1970s and earlier tend to produce fewer hotspots because their element designs do not create the same internal reflection paths. If you are getting hotspots with a modern converted lens, stop down two or three stops. This usually reduces or eliminates them. Changing the angle of the light source relative to the lens can also help. Dust spots on the sensor become much more visible in IR because the high contrast between bright foliage and dark skies makes every speck stand out. Clean your sensor before each shoot. Use a rocket blower first, then a sensor swab with cleaning fluid if needed. This adds about ten minutes to your prep time but saves you from spending hours removing spots in post. Another issue that catches people off guard is starburst effects on bright light sources. Infrared wavelengths diffract differently through aperture blades, so small apertures like f/16 or f/22 can produce unusually large and soft starbursts around the sun or streetlights. This is not a defect. It is physics. Decide whether you want to embrace it or avoid it by using wider apertures.

When Infrared Is Not the Right Tool

IR photography has real limitations. It does not work well indoors unless you have strong IR-compatible artificial lighting, which is rare and expensive. Cloudy days are actually better than bright sunny days for IR because the light is more diffused and you get fewer harsh shadows. Rain is fine, but water reflections behave differently in IR and can produce unexpected results that may or may not fit your vision. If you need to capture heat signatures rather than reflected infrared, you are looking at thermal imaging, which is a completely different and significantly more expensive category. FLIR cameras start around $500 for entry-level models and go up from there. Thermal imaging is useful for building inspections, electrical work, and search-and-rescue. It is not useful for the artistic IR photography that most people are interested in.

Resources and Where to Look

The infrared community is small but active. Rick Brewster's website at infrared-photography.net has extensive information about conversions, lenses, and techniques. The IR Photography group on Facebook has over fifty thousand members who share tips and troubleshoot problems. Reddit's r/infraredphotography is smaller but has a higher signal-to-noise ratio for technical questions. For buying conversions and filters, the vendors listed earlier are the ones I have used and trust. There are cheaper options on eBay, but the conversion quality can be inconsistent. A poorly done conversion with misaligned filters or improper sealing will cause light leaks and require another repair that costs more than the original conversion.

Final Notes on The Light We Cannot See

The whole setup and learning curve takes time. Budget at least three months of regular shooting before your images start looking like what you see in magazines. The first fifty or sixty photos will probably not be great. That is normal. The equipment investment for a basic setup runs about $800 to $1500 depending on what camera body you already own and which lens you choose. If you are serious about this, start with a used camera body you can afford to convert and a vintage manual-focus lens. The total cost is lower and the optical characteristics are often better for IR work than modern autofocus lenses. There is no single download or software shortcut that turns a normal camera into an infrared one. The conversion is hardware-level. But once you have the gear, the process is straightforward. Shoot in manual, focus manually, expose using the histogram, and spend time in post-processing matching the channels to your vision. The results are worth the effort.