INFRARED (IR)
Shooting between 700-1200nm is often referred to as 'Near Infrared' so as to distiguish it from thermal vision which involves higher wavelengths, but for simplicity I will refer to it here as simply 'Infrared', or 'IR'. Some of the shots I take start at 600nm and thus combine red and near infrared to get some kind of colour separation in the image. With some small manipulations it can produce a blue sky, but before I get ahead of myself let me talk about the different ways that you can shoot infrared photography...
What Does A 'Conversion' Entail?
Before I get into the different ways to shoot infrared let me explain what a conversion is and why it's necessary... All cameras are naturally sensitive to infrared but that sensitivity s blocked by an internal filter called a 'Hot Mirror'. This tends to be stronger on newer cameras generally because the more IR light it blocks the more accurate visible colours can be. Cameras can be converted to infrared (or dual-spectrum, or full-spectrum) by removing the 'Hot Mirror' and replacing it with something else.
1. Non-Converted Camera
Using external filters on a normal camera is usually the easiest and cheapest way to start with infrared photography, but there's a couple aspects to look out for. Some cameras are simply not sensitive to IR light, so try googling the model of your camera to see if anyone else has tried it first. If you can't find any information then try to borrow a filter. If this is not possible and you still wan to try then look for second hand or cheap Chinese filter. You're looking for a middle-ground wavelength here, something like 720nm (if you go higher than this it might get no image). If this does work on your camera then you're going to have a much lower exposure than with colour, so a tripod will most likely be needed. Also note that below 700nm usually gives little IR effect (mostly just red) and this usually means that you won't be able to have much colour separation with your IR.
2. Converting Your Camera to Infrared
This is quite costly, but if you're serious about infrared it will make things a bit easier. Unfortunately after conversion you will not be able to shoot colour again. IR conversions are recommended for DSLRs over Full-Spectrum.
3. Converting Your Camera to Full Spectrum
This is quite costly, especially because you'll also need to buy filters for each wavelength (and probably each filter size) on top of the conversion costs. If the idea of shooting infrared and colour with a single camera is appealing to you then this is for you. Full Spectrum conversions are not recommended for DSLRs, for mirrorless cameras they make a lot more sense.