From: utzoo!decvax!duke!harpo!ihnp4!ihuxk!rs55611
Newsgroups: net.rec.photo
Title: Re: RE:  How to use a flash
Article-I.D.: ihuxk.270
Posted: Thu Jan 20 15:48:45 1983
Received: Sun Jan 23 07:34:16 1983
Reply-To: rs55611@ihuxk.UUCP (Robert E. Schleicher)
References: ihuxm.152 houxz.250 ihuxf.184

Several people have recommended using bounce flash (tilted flash head)
as a means to eliminate "redeye", mentioning in their responses that
there is a loss of flash intensity that must be compensated for.
Some clarification is needed.  First, with automatic flashes, no
compensation is needed, as the light coming back to the flash sensor
has already bounced off the ceiling, and is therefore already less intense.
Thus, the flash (or the camera, in the case of TTL flash metering, as
on Minolta x-700) will automatically adjust for the bounce flash.
The thing which you have to be aware of is that the maximum flash
to subject distance over which the auto-flash will work properly has been
reduced.  Most auto-flashes with bounce heads have an indication on the
table on the back of the flash which shows maximum distance as a function
of film speed (this also shows the appropriate aperture for each film speed).
This table will often also show a reduced maximum distance when using bounce
flash (automatic mode only)  Aperture compensation at the camera is only needed
for manual flash mode.  Another warning:  Pictures taken with bounce flash
can be discolored if the surface that the flash bounces off of (prior to
getting to the subject) is colored.  Thus, bounce flash off of a white
ceiling works, while bouncing off of a painted wall (holding the camera
vertically, for instance) will cause coloration.  (Off-white ceilings
give a nice warming effect.)  Diffusers placed over the flash head
avoid this, and will also be automatically compensated for by
auto-flash operation.

Bob Schleicher
ihuxk!rs55611