Garden Fence

Garden Fence

First try with Infrared Filter


kat's picture


They are kind of similar but the wavelengths generated by heat and from light are different. My filter blocks out most visible light and only captures wavelengths longer than 0.72 micromenters. The image above was taken with a six second exposure at f5.6. That's why the trees in the background are blurred ;-) You can also see some colour in the image which is where some visible light has got through. Thermal imaging tends to use much longer wavelengths of light - typically around 3 micrometers and longer. I doubt many cameras are tuned to be sensitive to such long wavelengths as infrared actually degrades a visible light image as the focussing point is slightly closer for infrared than visible hence they tend to have stuff to stop the CCD being sensitive to it which is why I was concerned about whether I would get anything at all.

So after that long, boring, un-needed explanation, a candle shot with an infrared filter with my camera will look bright cause it gives off infrared information right from visible light wavelengths through the section with is just out of visible by my camera and into the heat related wavelengths which my camera has no hope of picking up at all.

Does that make sense?

Pat from Canvey's picture

Infrared and heat

What would happen if you tried this with a candle flame or am I confusing infrared with heat?