Oly 4, 1024x576 |
While playing with the idea of buying an IR filter, I tested the sensivity of my camera. What you see here is Jockal shaking his Sony MiniDV camcorder around for 16 seconds with its "NightShot" IR LED on. Looks like a deodorant or fashion ad to me. His face and the walls were illuminated by the camcorder's viewfinder which was the only visible light in the room.
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Oly 4, 512x384 |
My very first daylight NI image, taken on my way to work right after I got the filter. I didn't have a tripod, the sky was overcast, and the autofocus didn't work correctly... |
Oly 4, 686x514 |
A very strange effect occurs when I point the camera at a very bright spot, such as the sun or a light bulb, in IR mode: the light source is surrounded by a rectangular matrix of bright circular spots. I haven't come up with a satisfactory explanation for this phenomenon so far; it could be something like "multiple zig-zag reflections inside the filter glass" or so... |
Oly 4, 512x384 |
On the evening of the day I got the Hoya R72, I tried to hold still for a 16 seconds exposure under the 100 Watts of light in my room. Scary result :-) |
Oly 4, 1024x576 |
The railways west of the Regensburg central station, with allotment gardens in the foreground - this is the same view as seen in the "very first" image on the top right. This one here was one of the first really clear and well-focused NI images for me. |
Oly 4, 1024x576 |
Visible-light (RGB) version of the image to the left. |
Oly 4, 362x512 |
You may have heard of the trouble Sony had when people realized their "NightShot" equipped camcorders could effectively see through some fabrics (like bathing suits!) in daylight conditions (do a search for "infrared xray sony" or so on Google to see dozens of rather embarassing sites on this topic). Newer versions of Sony camcorders have been modified and totally overexpose daylight recordings when NightShot is active. (see here for an article about this effect) Bright sunlight, however, is exactly what you need for taking IR pictures with non-NightShot cameras, like my Oly C-4000Z - so I now realized my cycling shirt (made of polyester) is at least somewhat transparent to NI light. You can see the shape of my undershirt and the textile stripes sewn to the back of the zippers. |
Relatively soon after getting the filter, I took pictures of a light spectrum ("rainbow spot") caused by the sun shining through a decorative crystal in my living-room window. I used the images (the RGB and the NI version) as colored "height_field"s in POV-Ray to get a very rough spectral sensivity graph, and here is the result. "w/NIRP" means the respective channel with the Near Infrared Pass filter on the lens. The "red w/NIRP" channel is enormously overexposed and I will try to get a better version of this graph sometime soon.
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