DPanswers

essays | home

IR and Lenses

by Gisle Hannemyr

This page is part of a series of articles about digital infrared photography. The complete set of segments in this series is:

Table of Contents

  1. Introduction
  2. Fixed Focal Length Lenses
  3. Zoom Lenses

1. Introduction

image showing hot spot
Typical hot spot.

In addition to the sensitivity of the sensor the quality of digtal infrared depends on the characteristic of the lens.

For example, the Canon EF-S 18-55mm f/3.5-5.6 typically produces a pronounced hot spot as can be seen in the sample picture to the right. The hot spot is a result of internal reflections within the lens produced by the lens' coatings. Some types of coating are not transparent to infrared wave­lengths.

Also note that almost any lens will exhibit more flare and ghosting at infrared wavelengths, compared to when it is used to capture visible light.

Below is a preliminary list of various lenses and whether they are suitable for digital infrared or not. The list is not a result of systematic testing, but com­piled from observations submitted by readers. The lenses listed in the intermediate category - May produce a hot spot, etc. - are those where I have inconsistent reports, or where the hot spot, flare and/or ghosting is so unobtrusive that modest post-processing will clear things up.

If you want to add to the list, or comment on one of the entries, please use the comment facility in my blog. If you want to read the original comments by the testers, and not just the summary below, the blog is also the place to look.

The recommended way of testing a lens' susceptibilty to the hot spot problem is to make an IR photograph of a sheet of white plain typing paper.

2. Fixed Focal Length Lenses

Recommended for IR

May produce a hot spot, etc.

Gives hot spot

3. Zoom Lenses

Recommended for IR

May produce a hot spot, etc.

Gives hot spot

Lenses marked with a (*) has been tested by me.


If you want to add a lens, use the blog!

About DPanswers | Terms of Service | Privacy Policy | FAQ | Contact
Copyright © 2009 Hannemyr Nye Medier AS. All rights reserved.