Re: Photographing arcs and sparks
Posted by Bert Hickman on 11/28/2007, 1:54 pm, in reply to "Photographing arcs and sparks"
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: What techniques work best for imaging focused ambient room / environmental
: details and capturing sparks?
I assume you mean sparks from a Tesla Coil?
The best pictures will be taken in the late evening or at night, and (if outside) with little or no wind. Use a tripod, and shine a tungsten-filament light source onto the coil so that you can see the coil in the shot. You may also want to add one or more breakout points on the toroid in order to direct sparks to the right or left of the coil, since sparks heading toward you won't look right (and may be partially out of focus), and those heading away from you may be invisible when blocked by the toroid and secondary.
Using an external light source instead of, or in addition to, the camera's flash will also permit you to focus properly on the coil itself. If you can, fix the focus onto the toroid to prevent the camera's autofocus function from trying to focus on constantly moving sparks. Try shooting with or without a flash to see which works best. The best results will be with the camera set to MANUAL mode with color balance set to TUNGSTEN. The exposure time should be set to somewhere between 1 and 4 seconds, and "film" speed set to ISO 200 or 400. Faster film speeds may result in grainy pictures, and slower speeds may make the sparks look too dim. Longer exposure times may cause the picture look overly "busy" with too many sparks, but this can sometimes result in very spectacular pictures. Experiment with what looks best.
Most digital cameras are quite sensitive to near infrared - this will make your sparks tend to look brighter and fatter than they really are. You may also want to try setting your camera for burst mode to capture a sequence of pictures as the coil runs over an extended period of time. You can also try using a vertical grounded rod to create a series of sparks from the toroid. These can form moving arcs which create some very pretty "banjo" effects, where individual sparks are slightly offset, resembling a series of glowing banjo strings.
If you have excessive noise from "hot" pixels in the camera during long exposures, try using one of these tools (or Photoshop):
Here are some tips:
Finally, be very careful when running Tesla Coils in the dark. Be sure you know all spots where dangerous high voltages lurk and stay well away from these areas.
Good luck and best wishes,