Lens Considerations

As stated previous normal photographic lenses are designed for visible light photography and can sometimes behave quite strangely in infrared light. This page covers the most common lens problems when photographing in IR light. Just something for you to think about and be aware of when working in infrared.


Lens Hot Spots

Lens hot spots is the most common problem encountered when shooting infrared light. They usually manifest in the form of a bright circle, sometimes in the shape of aperture leaves directly in the center of the image. The problem is exaggerated as you stop down (increase f stop number), with the spot becoming more prominent and defined.

Captured with a Canon T2i and 50mm 1.4 prime lens at f22.

Hot spots can be caused for a variety of reasons, the most common of which is the coating on the inside of the lens barrel being reflective in IR light. Another frequent reason is light interaction between the coatings of the lens elements. A less common reason is light interaction between the lens elements and the imaging sensor(usually the micro-lenses) in the camera. In this case using the lens on one camera model may have no hot spot issues and on another model there could be prominent hot spots.

Unfortunately, if your lens has this issue the only solution is to simply use a different lens altogether. Fortunately the majority of lenses don’t have this problem or the problem is very minor and normally not visible in images. We are compiling a list of lenses we recommend people avoid as they have been proven to have hot spots with every model and lens copy:

Canon Lenses Nikon Lenses
50mm 1.4 24-70mm 2.8
16-35mm 2.8 35mm 1.8
16-35mm 2.8 II 24-85mm AF-S 3.5-4.5G ED VR
20-35mm 2.8
28-70mm 2.8
24-70mm 2.8 II

Wide Angle Distortion

You may have noticed in your images of buildings that sometimes the vertical or horizontal lines seem bent, especially at the edges of the image, this is barrel distortion and is present to some degree in all wide angle lenses. As a rule of thumb the wider the angle, the more distorted the image.

No Distortion

Barrel distortion

Pincushion distortion

These distortions are also present in IR and in some cases are more pronounced due to the longer wavelengths. The following lenses seem to be the worst offenders:

Canon Lenses Nikon Lenses
EF-S 10-22mm f/3.5-4.5 USM 10-24mm f/3.5-4.5G ED
EF 8-15mm f/4L Fisheye USM 12-24mm f/4G IF-ED
14-24mm f/2.8G ED

Lets proceed to the next section: NEXT Camera Considerations