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How can I tell if my camera will do infrared?
Digital camera sensors are just as sensitive to the infrared spectrum as they are to visible light - the problem is that most manufacturers intentionally try to limit the amount of IR hitting the sensor by placing an IR blocker, also known as an IIRC filter or a hot mirror, in front of the sensor. So, it very simply comes down to how effective is the IR blocker in your camera? The reason you want to know this is simple: The better the blocker the longer shutter speeds you will need to get a decent IR exposure through them. I started years ago with a Nikon D50. This camera is extremely sensitive to IR. When I got my Nikon D80, and subsequent D90, I realized that at some point Nikon beefed up the effectiveness of their internal hot mirrors and I don't even bother trying with these cameras using a filter (unconverted). Yes there have been people out there doing IR with them, but in my experience it is a hassle dealing with the extra long shutter speeds necessary to burn a decent IR exposure through the internal IR blocker. Just for comparison, with the D50 on a normal sunny day I might be looking at 1/3 second to 2 second exposure times, where the D80/D90 would require 30 seconds to 1 minute for the same exposure. And in that time, all the leaves on the trees have blown, the clouds have moved - you get the idea. Much harder to get a sharp image.
So how do you tell if your camera will give you a productive run with IR photography before you spend the cash on an expensive filter? The best advice I can give is go online to a site like www.flickr.com, find a group for your model camera, join the group, and post the question to the group. Guaranteed someone in the group has tried it and can tell you their experiences. The second thing you can do is try the old TV remote test. This one is simple, your TV remote uses infrared, so aim it at your camera while pushing a button and take a shot. (Dark ambient light and a longer exposure works best, and on point and shoots or DLSR's with live view this is much easier because you can simply look at the screen and forgo the test shot.) If you see nothing coming out of the remote in your picture, you probably don't have the best candidate for an IR camera. if you see a spot of light coming from the front of the remote then you are seeing IR - the brighter the spot the more sensitive your camera is to IR.
I'll end this section with this statement: All of the above assumes you are going to use an external IR filter on your lens. If you plan on having a camera converted to IR-only, then throw all this out the window. Part of the conversion process involves taking the internal IR-blocker out, so at that point any camera that can be converted becomes as sensitive to IR as it previously was to visible light. I highly recommend conversion over external filters for several reasons that I will get into further down in this tutorial, as well as tell you how and where you can get your camera converted.
Do I have to convert my camera or can I use a filter?
Simple answer is yes you can use a filter and no you don't have to convert your camera. The picture below was done using a normal visible-light camera and an external IR filter screwed on the front of the lens.
What type of filter should I use?
This is probably the most common question asked of me on a regular basis. Without going into great detail on the infrared spectrum and wavelength cutoff points, I'll just say that I have used, and prefer, the Hoya R72, or sometimes listed as the RM72. It cuts off at 720nm, and I think the shots I get from this filter have a lot more flexibility in post-processing than you would get from some of the filters that have higher cutoffs (around 900nm) and yield higher-contrast images. Simply put, I think you get a great range of tones from this filter and it has been my IR workhorse and has served me well. I also find it to be one of the more wallet-friendly options.
I also like it because it is of the round, screw-on variety and not a square filter designed for a Cokin type holder. Don't get me wrong, I am a big fan of Cokin filter setups and use them all the time - but when it comes to infrared I believe that you want to prevent any possible light entering between the filter and the lens, and with the Cokin setups as we all know there is a gap there. some might debate this point, and there are infrared filters available for Cokin setups that I'm sure people have had success with. I am just saying that due to the opaqueness of infrared filters I would expect internal reflections between the filter and the lens to at some point be an issue.
I have already said that you use longer shutter speeds with filters and quicker shutter speeds with conversions. Here I will quickly explain why this is the case. As I mentioned digital cameras have blockers inside designed to filter out the infrared spectrum and prevent it from influencing the appearance of your visible-light photographs. The strength of these varies, but what they all have in common is a resistance, to some degree, toward IR. So when exposing an infrared image, to get the image past this blocker and onto your sensor, the longer the shutter stays open the more time the image has to penetrate this barrier and "burn" past it and onto your sensor. Again I will say that there are some advantages to slower shutter speeds as well as faster ones. The image below is a great example of what slower shutter speeds will produce:
The benefits of conversion and how to convert your camera.
At this point I'll jump right into what I consider to be the most important pros and cons of converting your camera over using an external infrared filter.
You could take from this, that if you decide that IR photography is for you then a dedicated conversion is the way to go eventually. I would agree with this, and would highly recommend the conversion services provided at Life Pixel. You can find tutorials for performing a partial conversion yourself after ordering the replacement internal filter from them, but I believe it is worth the money to have them perform the service. the reason I use the term "partial conversion" if you do it yourself is because when Life Pixel converts your camera they do a little more than just replace the internal filter - they perform an auto-focus calibration to compensate for the IR focus shift, set a custom white balance, and above all they know what they are doing and have disassembled hundreds of cameras just like yours. If the idea of de-soldering components inside your camera makes you nervous, send it to them!
I'd also like to do a tiny bit of self-promotion and sincerely ask that if you've found this tutorial helpful, and do decide to convert your camera that you please use the referral banner link above to order your conversion service from Life Pixel. I'll get a small referral bonus, and you'll sleep well knowing you've helped support a fellow photographer at no cost to you. :)