Photographing Your Coil

 

Updated:  Nov. 20, 2004

• Best results achieved using 100 iso 35mm film or 160 iso for 120 and 220 films, aperture wide open and 3 or 4 second exposures.  Generally, the slower the film the better the result although I've not yet tested 25 or 50 iso (black & white film only).  A tripod and cable shutter release really help for good results and use the 'mirror up' option if your camera has it as this reduces camera vibration (I've only seen this feature on medium format cameras).  And get that camera close enough to fill the frame with the action, don't be too shy, a yard or two outside of the strike range is safe.  FWIW - 35mm cameras used to be called 'miniature' cameras due to their tiny negative size and were considered toys.  Originally developed to use left-over 35mm motion picture film in the late teens or early 1920's when large format was the norm for 'serious' photography, e.g., 8" x 10" negatives.
• Computer Interface:  I have a device called 'Dazzle Movie Pro', it came with software and interfaces most any video device to my computer.  I mostly use it to read in a VHS video to my hard drive although any tape format, digital camera, cd or dvd can be used as well.  I can then edit or save individual frames, select a frame range to copy out to another tape format, cd or dvd or hard drive file and to create animated gifs.  I use Jasc Software's Animation Shop (part of Paint Shop Pro) to create gifs like the one on the 'Bi-Polar TC' page.  Very useful and cost around $300.00 a few years ago, it could be cheaper today.
• Digital Cameras:  I've not used my digital camera to shoot a discharge but will do so very soon (Ricoh RDC-7, 3.3 mega-pixel, no cable release but the delay compensates).  Most digital lenses are pathetic (tiny), but the ability to easily get images into a computer for manipulation and printing is a big plus.  However, I have recently seen some good Tesla photos taken with digital cameras, e. g., an HP812, 4 mega pixel.  Also, 8 & 9 mega pixel cameras with interchangeable lenses are now getting cheaper and the originator of digital camera backs, Leaf, currently makes 6, 11 & 22 mega pixel backs for Mamiya 6x7 format cameras ($7,000.00 to $23,000.00).
• Infrared film:  Store this film in a freezer and remove four hours before use.  Extremely light sensitive, load camera in a light-tight room.  Kodak Ektachrome Professional Infrared EIR.  Focus the camera to a point about 6" to 10" in front of the target (depending upon camera distance), some lenses will have an IR setting on the focus ring.  35mm only, I've been unable to locate 120 or 220 formats.
• IR Filters:  Red 25 for BW IR film.  For color IR film use 87 or 89 series filters.  There are at least four to choose from (87, 87B, 87C & 89) and perhaps others.  Sources include Kodak Wratten & Lee.  Look closely at the spectral curve of any filter before buying.
• Ultraviolet film:  All b/w and color films are UV sensitive, some more so than others, e. g.,  Ilford's Delta 100 & SFX200.  Spectral or sensitivity curves for a film (also called a 'wedge spectrogram') are available from the mfr.
• UV Filters:  47B, www.leefilters.com/, a very dark filter requiring a 3 or 4 stop compensation.  In dark or limited lighting conditions you'll need a long exposure and/or very close positioning of the camera to the event.  Use of this filter will require some experimentation.  Gel filters are the most economical.  I'll post some pics taken with this filter of one side of my bi-polar coil from about 12 inches away, nothing dramatic.
• Video Cameras:  Have you ever taped your coil and upon playback noticed interference in the recording?  I have and here's how I eliminated it:  Using some metal screen door type material, I created a 'shell' that enclosed the video camera.  It was basically a mesh bag, the back was open so I could insert the camera and the front was open for the lens (tapered at that end) and there were several smaller cut-outs so I could access the control buttons. After cutting the screen to size, I secured it to itself by pushing the metal strands through holes in the screen and bending them over (while fitting it to, or around, the camera).  I then laid a bead of epoxy along this joint.  Next I took a six foot piece of 60 strand grounding strap, attached an alligator clip to one end and screwed the other end to a three foot copper rod (0.5" o.d., one end sharpened the other drilled and tapped) which I just stuck into the ground next to the tripod.  This alligator clip was then clipped to the front of the screen.  The auto focus would range through the mesh but other cameras may need a cut-out in that area.  I use VHS format video cameras, other types may respond differently; however, I believe, ANY camera requires grounded shielding to produce good quality video/audio of an operating TC.
• Visible Block Filters:  I haven't used one of these yet but they do seem intriguing.  The VB filter passes IR & UV, blocking the visible spectrum.  As with all filters, look at the spectral curve as they vary with mfr.  I have to get one of these and will report back (with photos), could be interesting.
• More Photo Tips:  Here's a link to some great photo tips (and safety material) from Peter Terren's Australian website:  tesladownunder.iinet.net.au/Misc.htm#Photos - bad link 5-9-11
• Photo composition & lighting:  Peter Terren pointed out that I neglected to mention these two topics.  Inserting yourself or someone else into the picture with your coil in operation should be everyone's goal in achieving the ultimate Tesla Coil photo.  This provides some sense of scale (and danger) to the photo but also introduces you to the world of "advanced lighting techniques in photography" in order to find a balance in the exposure given the existing lighting conditions.  This will require some careful staging and practice to master. 
  • One trick you can use to bring out a person in the photo in a dark setting is to use a very dim light to illuminate the subject.  In a 3 or 4 second exposure this dim light will accumulate and show up in the photo as a brighter source than it appears (by your eye, in real time).  Keep that shielded light no more than 6 feet away and directed at the subject so that it won't wash out the coil or the discharge.  A reflective background/wall can also be factored into this equation.  Light-meters are nice and with film cameras they can be indispensable in this exercise, that and carefully noting all camera settings and distances as this has to be a repeatable exercise.  However, a digital camera will allow an image to be almost immediately evaluated; but, they do, typically, under-perform in low light shooting conditions.  Until proven otherwise, I insist on using film for 'dark'  or night-time shooting.  It's such a hassle, I just want the best possible photos, and I don't yet have that $23,000.00 Leaf digital back for my Mamiya RZ67.
  • An advanced technique - a double exposure (with you in it!) will be an interesting technical challenge, Tesla would sometimes have his photographer do this for him.
  • One last tip, force yourself to remain absolutely still while the exposure is being taken, hold your breath and, by your timing, give it an 2 or 3 extra seconds.

Tricks with Digital Cameras

If you want to get rid of the hot pixels from long exposures try taking a black frame (i.e. lens cap on) of the same exposure time, before (and possibly after) your shoot.

Then either subtract the black frame in Photoshop or use this:

http://www.tawbaware.com/pixelzap.htm

Also Neatimage (freeware, http://www.neatimage.com/ ) does a good job of removing noise.

Also the hot pixel problem is a function of the camera image detector and will not be alleviated by a Faraday cage as indicated in the Editors note. It is entirely dependant on the CCD chip temperature, exposure time and manufacturing faults.

6-14-11

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