buffyjean wrote:
Would someone please explain how to do infared photography
I don't think you have gotten very useful answers so far. Infrared is that portion of the spectrum just beyond red that our eyes cannot see, but a camera's sensor can. In order to prevent that infrared light from spoiling the image we are trying to capture, manufactures place a filter in front of the sensor that blocks most of the infrared light from reaching the sensor.
I say most, because the filters aren't perfect, and there is some leakage, however it is small. Some cameras allow more of this infrared to pass through than others. I have seen places on the web where someone has taken the time to collect information on which cameras can be used for this and which ones are not good for this, but its a moving target since new camera keep coming out.
A quick test to see if your camera is even sensitive is to watch through the camera and press buttons on a TV remote. If you can see the infrared light, then there is hope your camera can do it.
But the problem here is that very little infrared light is actually making it to the sensor, and once you place a suitable filter on the lens to block out visible light, you are facing long exposure times to get an image.
An alternative to this is to have a camera modified to be able to capture IR light. This involves the removal of the previously mentioned filter. And possibly a new filter that blocks visible light. There are arguments for both ways. I have one without a filter, more commonly called a "Full Spectrum" camera, and it is a must that I provide the correct filter on the lens. But I can pick from several different filters and get different effects.
The next step after taking the pictures is the processing. If you just look at the results, they look very red and not very pretty. You can turn that into B&W rather easily and get some stunning results. Depending on the filter used, the results can vary.
If you are using a filter closer to the red color such as 590 nm, or 650 nm or 720 nm, you can do a trick involving swapping the red and blue color channels and end up with something called psuedo colors that can be eerie, but beautiful. The lower the wave length, for istance, 590 vs 720, the more visible light is mixed with the IR light, and the results are different.
Should you buy or have modified a camera to do this, first of all, it works best if the camera can shoot RAW. You need the flexibility to adjust the White Balance a long ways to get the effect you are looking for, and JPEG doesn't cut it.
And also, it the camera came with a cheap "kit" lens, that lens may produce what is called a hot spot in the center meaning that the lens is not uniform on the amount of IR that passes through. I have a modified Sony A55. With the 18-55mm kit lens, I have a hot spot. With rather cheap Minolta Maxxum lens, which work fine on Sony cameras, there is no hot spot.
With a modified camera, IR photography can be very fun.