Infrared Photography (Part 1)

I have long been fascinated with infrared (IR) photography and have made the occasional attempt at it in the past using a Cokin IR filter on my DSLR, with variable results depending on which model I was using at the time. In this post I'll be talking about some basic principles up to some issues to consider when buying kit.

 

Digital photography sensors are inherently able to detect wavelengths from ultraviolet (UV) way into IR, having a sensitivity range from about 250nm through to well over 1000nm.

 

The thing is, for conventional photography that's a pain in the back side because it causes all sorts of colour casts from the sensor picking up bits of light that our eyes can't. In order to get round this, manufacturers place a blocking filter (often referred to as a 'hot mirror' filter although heaven knows why) which cuts out the UV and IR light, leaving just the visible spectrum of around 300-700nm and joy of joys, your pics look normal.

 

Luckily for people who fancy trying IR photography at minimal expense, many manufacturers' hot mirror filters aren't as strong as they could be meaning that, simply by mounting an infrared filter on the front of your lens, you may be able to try it out yourself. You will need to use long exposure times, often 5 -10 seconds, and therefore you will need a tripod but it's well worth a go. Apparently this is more an option for older cameras.

 

In time you will get fed up of lugging round that tripod and you will be frustrated with those long exposures meaning that trees in the wind are all blurred and stuff. The next step to think about is getting a camera that is converted either to a specific frequency of IR or to full spectrum. I'd strongly advise the latter for reasons that may be obvious but more on that in part 2.

 

So you'll be wanting a converted camera then? You have two options, convert a camera that you already own or buy one that's already converted. You may well have an old camera lying around following upgrading your kit, it may well be the same make as your current one so you can use all your lenses. Makes sense to get that converted and there are numerous companies around who'll do it for you, Google is what you need here. Last time I looked into it prices were in the region of £200-250 for converting a dslr which is a significant outlay for most of us.

 

Similarly, there are several companies that will sell you a ready converted camera. I'd advise checking ebay because you can pick up a converted camera body quite cheaply. I found a Sony NEX 5 converted to full spectrum for £95, around half the conversion costs I'd seen.

 

For that price I would suggest that you don't worry if the camera you find is a different lens fitting than your current kit. IR photography is mostly suited to landscapes so a kit lens is all you need (about £50 - 60 typically). And don't worry about the camera being 10 years old or more, you're not going to be needing 5 figure ISO capability. You may also see a few converted compact cameras which are fine but a) make sure they can shoot in RAW and b) check you can mount filters, especially if it's a full spectrum conversion.

 

One last thing to bear in mind. For reasons related to physics, digital slr cameras can have problems with autofocus when shooting with infrared. Mirrorless cameras are fine though. If you're looking at converting dslr do have a read up on this, there are workarounds and you obviously want your kit to do what you want it to do.

 

Hopefully that will help you go in the right direction when spending your hard-earned, see you in part 2.