Re: IR flash

[Otto Giesenfeld <otto.giesenfeld@xxxxxxxxxxxx>]

--On den 17 oktober 1999, 19:41 -0400 ADavidhazy
<ANDPPH@xxxxxxxxxxxxxxxxxx> wrote:

> Oh, I forgot to mention that the flash head or the flash itself did not
> suffer any ill effects either ... although I suspect that if you flash
> the flash often and at high power there is a chance of raising the
> temperature within the head to high levels. The operating word is
> "reasonableness". I think anyway.
> 

>From a physical point of view, there should be only three significant
heating effects by the filter (please correct me if I am forgetting
something):

1. The filter foil makes the cooling by air convection of the flash head
less efficient.

2. The filter partly reflects light from a flash back into the flash head.

3. Heat from the filter makes the cooling of the flash head slower, or even
makes the flash-head temperature increase for a while after the firing of a
flash.

This is assuming that temeparatures between flashes without the filter
would not exceed a few hundred degrees. (I.e. the irradiation of heat would
not be significantly hindered by an 87C or similar filter.) The first two
points would by the way be valid for any filter, including Skylight, UV,
etc.

I think the conclusion is that for a moderate intensity of flash use (in
terms of flashes per minute), the only worry should be about the filters
themselves.

Otto Giesenfeld

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