In Infrared (IR) photography, the film or image sensor used is sensitive to infrared light.
The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Usually an “infrared filter” is used; this lets infrared (IR) light pass through to the camera, but blocks all or most of the visible light spectrum.
I personally love shooting landscape in infrared because it give me dramatic feel.
Below is the sample of the infrared red photo converted into black and white photo.
After some post-processing, your infrared photo might look like the samples below.
The IR filter I using is the Hoya R72, all the IR photos in this article are taken using that filter. And most of the IR photos I taken was in 10~20 seconds exposure time. The longer the exposure the more noise will be created, so we would love the use the lowest ISO settings to try keep the noise level as low as possible.
Basically, I will use autofocus to focus on the landscape then I will set it to manual focus. Screw in my Hoya R72 filter into my lens before taking the photo. You will not be able to autofocus after the IR filter in place.