Re: B&W IR w/Flash

[mturner@xxxxxxxxxxxxxxx (Marc Turner)]

Paul,

Your lens aperture is way to small.  If you rate your HIE at 50 in daylight with
the 87C, it is somewhat equivalent to putting the 87C over your "daylight" 
flash.  To get a picture of a subject at 10 feet at f/16 with an EI of 50 would 
require a flash with output guide number of 320!  Guessing that yours is around 
110 at full power, you will need an aperture around 3-4 stops wider which is 
what your experiments indicated.  Try an aperture of f/5.6

- -- Marc

______________________________ Reply Separator _________________________________
Subject: B&W IR w/Flash
Author:  infrared@xxxxx at smtp
Date:    5/28/98 9:03 AM


Hi I'm new to the list (see bio below) and have a question about shooting IR 
with a flash. I have covered the flash with an 87c filter in hopes of taking 
discreet night-time photos. However, my first attempts at using this 
technique has produced negs that are consitently 3-4 stops underexposed when 
the subject is within 10 feet.. If the subject is any further away, negative 
density drops off to almost nothing
     
Anyone out there have any advice? Here are the particulars:
     
Camera: Nikon FE2
Camera settings: f/16; Exposure Index - 200ASA; Shutter - A 
Flash: Sunpak 433AF (Dedicated)
Flash settings: Manual; full power; 1000 ASA; 
Filter: on lens - none; on flash - Kodak Wratten 87C 
Film - Kodak Highspeed IR
     
Thanks,
paul
     
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