From: utzoo!decvax!harpo!eagle!mhuxt!mhuxi!mhuxj!mhuxv!burl!sb1!ll1!ihldt!ihnp4!gjm
Newsgroups: net.rec.photo
Title: Re: RE:  How to use a flash
Article-I.D.: ihnp4.178
Posted: Fri Jan 14 13:43:01 1983
Received: Sun Jan 16 04:14:36 1983
Reply-To: gjm@ihnp4.UUCP (G. J. Murakami)
References: ihuxw.276


The strange appearence of people's eyes in many flash photos is typically
referred to as "red eye".  This condidtion is caused by direct reflection of
the flash off of the retina.  "Red eye" is most apparent when the flash
to subject's eye path is nearly parallel to the path of the reflected light
from the subject's eye to the camera lens.

So tilting the flash head for bounce as Katie suggests will eliminate the
condition, but also cuts down on the effective range of the flash unit (less
of the light output from the flash reaches the subject).  If you are indoor
with good reflecting ceilings and walls, bounce should be an effective
measure with even pleasing effects.  However, it is ineffective outdoors
because of the lack of reflecting surfaces.

The standard way to reduce "red eye" is to move the flash source "off center"
away from the lense as far as necessary (or possible).  This is why some
of the pocket 110 cameras supply you with a stalk to mount the flash cube
away from the lense.  Bracket mounts or flash extensions can also be used,
but you must be aware that many flash sensors are attached to the flash head,
so moving the unit also means moving the sensor away from the lense (where it
is the most accurate).  Many flash systems offer "remote sensors" to mount
on the camera for off-camera flash.

Note that it is the angle that is critical, so close subject usually have
less problem with "red eye", while subjects at longer flash ranges require
the flash to be farther off-camera to eliminate the condition.

Gary Murakami
ihnp4!gjm