If you can stretch your budget, a used K5 would be a much better bet than the K10 or K20, it's a far more capable camera, and also weather-resistant. It also has usable Live-view, and much better low-light performance. They come up for sale on here in the classifieds section fairly regularly. The last one sold on here went for £330 including the weather-resistant 18-55mm kit lens. The only thing to look out for is the shutter count, the lower the better, I personally would think twice about buying one with over 50 000.

Excellent, I'm planning on getting an 18-35mm next month...

Set aperture priority, crank the ISO up to 6400, use maximum aperture for the lens, and just keep it pointed at the grass for as long as it takes to get a WB reading, probably a couple of seconds.

David, you need to set the WB with the filter on; have the lens wide-open and point it at some grass to set a WB. Lightroom/ACR can't cope with a colour temperature below 2000K, though LR 5 works better than previous versions. If you have any problems with WB in Lightroom, you can make a custom profile, or I can send you one, though it's for my Sony; I'm not sure if it'll work with the K3 but I will try it out.

There's some really useful stuff on making an infrared camera profile here . Just miss out the part about selecting it as default (or it will change all your K3 images to the new profile), just select it in LR/ACR when processing IR.

There's also some very good info on IR processing plus a free faux-colour Photoshop action here

It sounds like the WB was not set correctly if the whole image was reddish-orange, David. You should get some blue/cyan as well with an R72 filter. If you set the WB from some green foliage, preferably grass in sunlight, you should get more colour from the images.

That sums it up pretty well: Pentax are not presenting their products the right way IMO. Olympus manages to promote the OM-D as a "pro" camera, yet the K3, which is a better machine, keeps getting reviewed, and seems to be generally considered as, an "enthusiast" camera.

I think I would have tried to stop that a bit earlier than she did...

Thanks, Barrie!

Like the K3.......double the rated shutter life of the OM-D, weather sealing, etc etc

What makes a "pro" as opposed to an "enthusiast" camera? I find it very odd that the OM-D, with a 4/3rds sensor (and the E5 before it), is considered a "pro" camera, while the K3, with a larger sensor and similar specs, is considered "enthusiast". To me the lines between entry level/enthusiast/pro cameras seems a bit arbitrary. Pentax, with the Ltd. lenses, is more than a match for the OM-D with it's Pro lens line-up. DXOMark scores the K3 ahead of the OM-D in all categories on their Sensor Score link

Maybe Ricoh and Pentax maybe missed a trick by not promoting the K5/K3 as a "Pro" camera? The camera-buying public, especially those upgrading, are very prone to hype, and Olympus make much better use of that fact than do Ricoh/Pentax.