Re: Getting good digital photos

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: dhmccauley-at-spacecatlighting-dot-com 


Actually, it the settings depend on lots of things.  What Dr. Resonance
doesn't tell you is the film speed which is just as important as the
exposure length and aperature
as well.  Also, what works for a large coil with bright, thick streamers,
usually doesn't work well for smaller coils with purple streamers.

For mid-size coils (about 2kW to 3.5kW), I find that a f/2.8, 1 or 2 second
exposure looks best using ISO 800 film speed.
The photo below is shot at f/2.8 for 2 seconds using ISO 800 on a Canon
Digital camera.  The picture came out quite well, although it had to be
adjusted in Photoshop
to make it a bit brighter (levels adjustment) and also converted to black
and white (channel mixer)
http://www.spacecatlighting-dot-com/teslabw_gallery/bigimages/teslabw01.jpg

Its also important to realize that low power coils are the most difficult of
coils to capture photographically.  This is because the streamers are
typically purple and much less
bright then higher power coils streamers.  Also, most lens glass attenuates
light at the purple to UV portion of the spectrum quite readily which adds
to the difficulty.

Dan




 > We use a tripod with timer delay on the camera at 4 sec. exposure at f2.8.
 >
 > It also helps if you have a straight vertical ground rod --- the sparks
 > "climbs" due to the heating of the air and produces very exciting spark
 > photographs --- the sparks look thicker than in reality.
 >
 > Dr. Resonance
 >
 > Resonance Research Corporation
 > E11870 Shadylane Rd.
 > Baraboo   WI   53913
 >
 >  >
 >  > Some of you will have noticed, as I have, that many Tesla coil shots on
 > the
 >  > web are blurred, out of focus or are just don't convey the size of the
 >  > sparks/streamers.
 >  >
 >  > May I give a list of suggested criteria that I use for digital cameras
(I
 >  > did win an award for my cover shot on my site - well a small one
anyway)
 >  >
 >  > - Always use a tripod (or stack of bricks or the previous model TC).
For
 >  > medium exposures of seconds a hand held camera will blur a lot. The
sparks
 >  > will be sharp but the rest will be blurred.
 >  > - Make sure you get the end points of all the sparks to either side.
 >  > Chopped off sparks don't really give the impression of size. (that is
 >  > unless you do a Richard Hull and have sparks ONTO the camera)
 >  > - Try to get the sparks at a right angle to the camera by using a
breakout
 >  > point or grounded object.  Only by doing this will you see the full
spark
 >  > length in comparison with a fixed measure (which is usually the
secondary
 >  > winding height).
 >  > - Have a person in the background for scale (at a safe distance).  Even
 >  > Tesla himself got this right in his photos (admittedly with double
 > exposures).
 >  > - Adjust the background lighting to be able to see the surroundings for
 >  > scale. It is best to at least partially cover the spark gap as this
tends
 >  > to wash everything out.  It should have a shrapnel and UV guard on
anyway
 >  > shouldn't it?
 >  > - Fix the focus on the TC toroid with lights on, hold the focus, then
 >  > lights off, sparks on and shoot. This is needed as you can't autofocus
in
 >  > the dark. You may need to grow extra hands for this.
 >  > - Let the camera do an auto exposure and it will finish when it has
enough
 >  > light (may be 10 seconds on my camera).
 >  > - Don't put a large number of shots on your site. You choose the best
 >  > one(s) to save others the trouble of downloading many.
 >  > - I use thumbnails linking to a largish size of compressed photo of
200 -
 >  > 400k but I am very choosy with the photos and lots get discarded.  I
keep
 >  > the resolution full (4 megapixel before cropping) but reduce the colour
 >  > spectrum from 24 bit to 16 bit to save space. I can't tell the
difference.
 >  > - I use some RF protection if my camera close up to the coil with a
metal
 >  > can made for the purpose.  I have previously used aluminium foil to
wrap
 >  > the camera with lens sticking out.
 >  > - Avoid windy times (unless you want to show the banjo effect) as it
makes
 >  > the streamers look blurred.
 >  > - (I might add if in Australia, don't hold your baby up in front of the
TC
 >  > for publicity shots).
 >  >
 >  > Any suggestions welcome particularly about using film cameras.
 >  >
 >  > Cheers
 >  > Peter (Tesla Downunder)
 >  >
<http://members.iinet-dot-net.au/~pterren>http://members.iinet-dot-net.au/~pterren
 >  >
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