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Canon DSLR Challenge | all galleries >> CSLR Challenge 80: Bokeh (Host: Sharon Lips) >> Exhibition > LED
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23-JUL-2006 Victor Engel

LED

Canon EOS 10D ,Canon EF 300mm f/4L IS USM
1/3s f/4.0 at 300.0mm iso200 hide exif
Full EXIF Info
Date/Time23-Jul-2006 21:24:42
MakeCanon
ModelEOS 10D
Flash UsedNo
Focal Length300 mm
Exposure Time1/3 sec
Aperturef/4
ISO Equivalent200
Exposure Bias
White Balance (-1)
Metering Modematrix (5)
JPEG Quality (6)
Exposure Programprogram (1)
Focus Distance

other sizes: small medium original auto
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Canon DSLR Challenge08-Nov-2006 04:37
Victor, this one is highly unusual. I read it a few times, but I didn't get it completed. I think its some kind of interferences between the lights refected by the two surfaces of the glass of the mirror. LEDs emmit pure frequencies + plus the spider-eyed lens on top of the LED works as a lens and has a prism effect and is spreading the frequencies in a broader bandwidth, allowing it to mix well and cause the interference.
Very well seen and captured. -Cat
Canon DSLR Challenge04-Nov-2006 17:18
Yes, it is. Nothing but bokeh here. -- Victor
Canon DSLR Challenge04-Nov-2006 16:12
Fascinating patterns, Victor. It looks like a picture of bokeh itself. Very creative! ~Sharon
Canon DSLR Challenge04-Nov-2006 16:02
I copied this to the Bokeh Exhibition gallery, because I think it's worthwhile to explore what's going on here. -- Victor
Canon DSLR Challenge26-Jul-2006 03:57
By the way, if anyone thinks they know what is going on here, I'd really like to hear your ideas. My instinct is that we're seeing interference patterns of bullseye shaped features that are themselves a result of diffraction. What causes the diffraction? Dust on the mirror? Dust on the light? Dust or other features in the lens? Something supporting the last idea is a look at the full frame view, where you can see concentric rings just inside the overall circle. -- Victor
Guest 25-Jul-2006 23:36
This is a very cool exploration of light, Victor. Great patterns and color. -Michael
Canon DSLR Challenge24-Jul-2006 06:16
SPOILER! -- If you want to guess what it is, read no further. I'm not sure how to explain what this is. I first noticed the effect with my eyes, but not with so much detail. I recently bought a bunch of flashlights of various kinds for a baloon project (my other entry is a picture of balloons illuminated from the inside). One of the flashlights is one intended to be used as a forehead mounted headlight for bicylists. I've been wanting one for a while. The one I bought has a lens arrangement similar to the eyes of a jumping spider: two large lights with telephoto lenses, two smaller lights with wide angle lenses, and two other red lights.

I cleaned off a large area of the mirror in my bedroom and then shone the light at it so that I was illuminating myself through the mirror. I noticed that when I did this, I could see a sort of grid pattern around the light. I didn't know if this was an optical illusion of some sort or whether it was a real phenomenon. So I mounted my camera onto a tripod and took some pictures. What you see is a picture of the light from across the room with my 300mm light focused as close as it will go. In other words, it is out of focus. What you see is the bokeh of the light. I suspect that what is happening is that since the light source is an LED, the light is of uniform wavelength (or several uniform wavelengths). This results in clearly distinguished interference patterns, not unlike Newton rings. I suspect that some of what you see is also the result of diffraction around blemishes either on the flashlight or on the mirror. The diagonal bias is caused from my angling the flashlight to the side -- so it's only the rays going out the side of the lens that are captured.

As I said on dpreview, postprocessing is minimal -- levels, and USM/gaussian blur performed separately by channel (blue had the largest radius -- green the smallest). There is also very little noise in the picture. What looks like noise is really interference patterns.

-- Victor
jnconradie24-Jul-2006 05:36
Interesting, Victor! I also read your post in the discussion thread, but I am afraid I will not be able to offer explanations. I would love know to what you photographed? Regards ~jnconradie