Out of Spectrum Photography
Last year I got intrigued by IR photos found somewhere on the Internet. After a further investigation, I decided to try it out by myself. I bought ZWB2 filter, which basically blocks all visible light, while passing most of UV and IR. Filter's transfer functions I took a few photos but the results were terrible. In order to get any but pure black image I had to use a strong UV source and a few second exposure time, otherwise the image was pure black. photo with filter, 3s exposure photo without filter, 1/60s exposure The results were promising but where this huge time difference come from? One possible explanation would suggest that the camera is over 200 times less sensitive to UV than to the normal light (including blue nearby). Answer to this is as follows: filter at its peak transmits 80% of UV light lenses have many glass parts and glass stops UV (later I found that anti-reflective coatings make it even worse) sensor itself contains exactly opposite filter, which cuts out