w...b you said that you've read that HD camera's have better colour and such. But that's not true. First of all, most of these HD camera's have CMOS censors. And with motion such camera's are bad. because of the cheap shutters the image get weird with motion. What it does is that when you pan (go from left to right with your camera) a straight bar (for example the street lights) will get oblique because of it's shutter (google it for more information).
And what Coen already said is that when you buy an sd camera with the same price as an HD camera, the sd camera will have better quality because you pay for the extra pixels in an Hd camera.
Check google for the differences between CCD CMOS and 3CCD. If I were you, I would buy a 3CCD camera. They come in both SD and HD, but go for the SD. (3CCD HD camera are also way more expensive). 3CCD beats every HD CMOS camera in colour. There's 1 chip for each colour (that's red, blue and green). So you have dedicated chips that interpretate the colours better than one chip would by interpretating all colours on it's own. So SD has better colour (although, when you're outside the differences become pretty small as all camera's make good quality with good light, sunlight. It's going about the inside recordings).
Because you want enough light, so you don't get dark pictures or pictures with noise because of the gain, check the chip for it's size. The smaller it is, the harder it is for the chip (3CCD,CMOS or CCD) to have collect enough light (that's logical). So try to buy one with a not too small chip.
But that doesn't matter when you're shooting outside, cause there's enough light.
You're making an instruction video. So you need to be audible. All camera mics (mic=microphone) are pretty much crap. So when you have an HD camera with 5 mic's to get surround sound, you get 2,5 times more the crap. So it's not better. Only nice to have it surround.
But as you won't go spinning around the camera, and stand only in front of the camera, you won't need it.
What you need is a good mic with it. You need to buy an external mic. For example the RODE video mic. Or get a set from e.g. sennheiser, with a wireless microphone on your head or jacket.
To connect such microphones you need a camera that has at least a mini jack microphone input. (XLR will be better with more expensive microphones, but maybe a little bit too expensive).
So what do you need if you ask me:
A camera:
with 3CCD
not too small chips that "collect" the light
an external mic
ps coen je zei of i.p.v or bij the sd resoluties