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P3D RE: Question on use of flash guns
- From: "David W. Kesner" <drdave@xxxxxxxxxx>
- Subject: P3D RE: Question on use of flash guns
- Date: Sat, 12 Jun 1999 17:43:44 -0600
In p3d digest 3350 Dr. T. asks:
> I wonder how useful flash guns and flash bulbs are for stereo
> photographers today?
Very useful under the right circumstances.
> I undestand that flash bulbs deliver much
> more light than regular compact flash units
In most cases, much more light. The average strobe is in the GN
range of 80-100 (at 10 feet with ASA 100). The Vivitar 283 claims
120 which is about as powerful as you can get without going to one
of the monster "potato-mashers" and even then they are only about
150-160. An M3 or Press 25 bulb is good for about 180
(depending on what kind of reflector you use).
> and that some stereo
> photographers who need lots of light (like those exploring caves)
> sometimes prefer flash bulbs to electronic flash. Is this correct?
Yes and no. A lot of cave photographers still use bulbs, but more
and more are going with multiple strobes fired by slaves (the
electronic kind - although many still use humans). One of the things
you can do with a bulb and not a strobe is fill up a pie pan with
about a dozen or so bulbs and fire them all at once to light up that
50 foot wide by 150 foot tall pit. (Did you know that a bulb will fire if
it is near another bulb that goes off? Ask any old time press
photographer to show you the burn scar on his leg from a pocket full
of flash bulb going off unexpectedly).
> Any other reasons someone would use flash bulbs?
Two main ones come to mind. One is that it is a much broader light
than the narrow strobe. It is like the difference between a flood light
and a spot light. This of course can be modified and varied
depending on the reflector you use. Some like the folding fan
reflectors can be set in different configurations. The other deals
mainly with delayed exposures where the shutter is left open for the
full duration of the bulb's burn time. As the bulb comes up to full
intensity and then down again as it burns out it gives off colors. This
can translate to a much "warmer" image. Especially when
compared to the bright harsh light of a strobe.
> Also, are flash bulbs made today new or do these people rely in old
> stock?
Both. There is a company that has just recently started
manufacturing bulbs again. They are in Europe somewhere (don't
have that info handy). The bulk of their production is in the really big
household lightbulb sized screw base bulbs (talk about a high GN).
Everyone that I know that still uses bulbs gets them used from old
stock either at yard sales, the back room of the camera store, or
from someone who horded them throughout the years. You take
your chances on price. I have seen them from $1.00 for a single
bulb to a box of 12 for $0.50. Ebay always has some up for sale at
rediculous prices.
Do not forget that bulbs come in clear and blue. Clear is for black
and white and blue is corrected for color film. Some flash guns have
blue accessory covers for clear bulbs. Many old photo books also
have formulas for making your own blue shelac to coat clear bulbs.
Hope that is not too much info.
That's all for now,
David W. Kesner
Boise, Idaho, USA
drdave@xxxxxxxxxx
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