Re: IR Flash

[Fred Greenspan <greenspan@xxxxxxxxxxxxx>]

Thanks for replying Dave. All your advice sounds promising. I already did some
indoor tests today with both films that I am testing, using a red filter over
flash for some, and tungsten lighting with and without lens filter for others.
I do keep careful records. I use a hand held Sekonic to meter my flash, as
well as take incident readings of the tungston lighting. I used an EV with the
filter factor built in, trying both 2 and 3 stops over for each film. All my
negatives came out well exposed, but it will take a few days to print and
fully evaluate my results as far as IR effects.

You may have mixed in my original questions with someone elses, as I was not
looking for a sturdier filter for over the flash, I already have one that came
with the flash.  The filter on the film rails doesn't apply to me either, as I
am using TLRs and rangefinder cameras, but I'm sure it will be useful info for
others. From what you said about Electronic flash, it sounds like it would be
worthwhile to try using my studio flash units with the 092 on the camera lens.
Today I just used a small flash that came with a hard red snap on filter to
see what it would do. Thanks!-Fred

David J. Romano wrote:
> 
> Fred,
> I have used a flash with IR film, I've even metered for it by putting
> the filter over the flash meter's sensor. Flash tubes are Xenon and
> output alot of IR, right where we need it. If you intend on doing alot
> of flash IR work, your best option is to place the filter between the
> film rails so that you can still see through the viewfinder. Next you
> need to do a test. Don't waste your time and money expecting to get
> lucky with trail and error. Always test and keep records. Set your flash
> to full power, and do an exposure series photographing your subject at a
> distance of 10 feet. Change the exposure by changing the aperture, not
> the shutter speed. Develop as normal and look for the best exposure. The
> aperture that was used multiplied by 10 is your flash's IR guide number.
> Be sure not to use the flash's auto setting. The auto setting uses a
> light sensor mounted on the flash, which I suppose you could mount an IR
> filter in front of, but that would be another test altogether.
> 
> If you really want to mount a filter in front of the flash and would
> like a sturdier filter try buying one from Edmund Scientific at
> www.edsci.com. They sell one which is made of optically correct thermal
> resin. A 4x5 piece of it is only 12 bucks.
> 
> Good luck
> 
> Davee
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