Did you know that you can photograph invisible light? Full spectrum infrared cameras can see beyond what you and I can perceive with our eyes, providing a unique way to view the world.
Lightwaves within the visible spectrum are between about 380-780 nanometers, but there is light outside of what the human eyes can see. On one end is Infrared, also called Thermal Radiation, which is from 780nm to 1 millimeter (700nm to 780nm is sometimes referred to as near-IR). On the other side is Ultra Violet, which is from 380nm to 10nm. Camera sensors are sensitive to these lightwaves, so manufacturers place a filter over the sensor to block the invisible light. If not for this filter, your pictures would look abnormal compared to what your eyes see. Full spectrum cameras don’t have this filter, and are sensitive to the full range of lightwaves.


Above: Full spectrum images without filters, photographed on a Fujifilm X-T4 ES.
Fujifilm has made several full spectrum cameras. First was the S3 Pro UVIR in 2006, followed by the IS-1 (infrared version of the FinePix S9100) in 2007, then X-T1 IR in 2015, then GFX100 IR in 2020, and finally the X-T4 ES (“Extended Spectrum”) in 2024. Typically, Fujifilm does not offer these models to the general public; instead, they are strictly only for “forensic, scientific, and cultural preservation applications.” The X-T4 ES is the first full spectrum model that Fujifilm has sold to the general public, albeit quite quietly. As of this writing, I believe that the only place you can buy the Fujifilm X-T4 ES is from B&H, but it requires a phone call or in-person visit, and cannot be ordered from the internet. If that changes, I’ll be sure to let you know.
For those unable to buy a Fujifilm X-T4 ES (which is a standard X-T4 just without the infrared/UV filter over the sensor), you can convert any Fujifilm camera to full spectrum. It requires an expensive and invasive procedure from a third-party vendor like LifePixel, Kolari Vision, or Spenser’s Camera (there are others, too). Sometimes you can find an already converted camera for sell. You can also get a specific infrared filter over the sensor in place of the removed filter, but that is a much more limiting approach than a full spectrum conversion, and you have to know that you’ll be happy with your filter choice before committing to it, or else you might find yourself regretting your decision. The easiest option—if you can find it, which might be a big if—is the X-T4 ES. I hope that Fujifilm makes this model (or something similar) more easily available to purchase.


One consideration for full spectrum cameras is the lens. Many lenses suffer from IR hotspots, and can perform less than optimally when used with a full spectrum camera. Many lenses are good wide-open at maximum aperture, but as you stop down the hotspot appears. The Fujinon 35mm f/2 is good at all apertures, and that is the one that I most commonly use with the X-T4 ES. There are several databases (here, here, here) for which lenses are good for full spectrum cameras, and which ones to avoid.
Another consideration is filters. You don’t need a filter to use your full spectrum camera, but you can use various filters, such as the Kolari Vision IR Chrome, to control the wavelengths of light that hit the sensor. You can achieve many various looks by the filters you use in conjunction with the camera settings, including film simulation and white balance. These filter and camera setting combinations are called Full Spectrum Film Simulation Recipes, which allows you to achieve striking photos without editing. As of this writing, I have published five Recipes: Aerochrome v1, Aerochrome v2, PurpleChrome, Cotton Candy Chrome, and Agfa 400S. More are in the works, so stay tuned for that.


Clockwise, from top-left: Aerochrome v1, Aerochrome v2, PurpleChrome, Cotton Candy Chrome, Agfa 400S.
Capturing the invisible light spectrum is extremely fun and rewarding because it transforms an ordinary scene into something truly extraordinary. The world becomes a fanciful place filled with unexpected colors. It’s like a crazy dream, except that it’s real, if only you could see it—full spectrum cameras allow you to peel back the curtain and take a peek.
Interestingly, you can actually do infrared photography with non-converted Fujifilm cameras, because the X-Trans sensors are sensitive to near-IR light. My Full Spectrum Film Simulation Recipes won’t work, because those require a full spectrum camera like the Fujifilm X-T4 ES, but nonetheless you can still do IR photography with a 720nm IR filter (which blocks most visible light) on a regular, non-converted model. It’s fun to try! Since most of the light is blocked, you will be using high-ISOs and/or longer exposure times. If you do this, be warned: you might get bit by the IR bug, and find yourself converting a camera, or searching out an X-T4 ES.

Above: B&W IR photo from a non-converted Fujifilm X-E4 & 720nm filter.
See also:
Photographing in Aerochrome
Philadelphia in Aerochrome — Infrared Photography in the City of Brotherly Love