# Causes of and avoiding red eye in photos **URL:** \ **Category:** Factual Questions\ **Created:** [March 13, 2003, 12:03pm UTC](https://boards.straightdope.com/t/causes-of-and-avoiding-red-eye-in-photos/161076 "2003-03-13T12:03:32Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![antechinus](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@antechinus](https://boards.straightdope.com/u/antechinus)\ **Post date:** [March 14, 2003, 1:52am UTC](https://boards.straightdope.com/t/causes-of-and-avoiding-red-eye-in-photos/161076/21 "2003-03-14T01:52:42Z")
Hang on… From [http://www.cis.rit.edu/people/faculty/montag/vandplite/pages/chap\_8/ch8p3.html](http://www.cis.rit.edu/people/faculty/montag/vandplite/pages/chap_8/ch8p3.html) > [@](#): > > In class, I try to borrow an ophthalmoscope so that the students can look into each other’s eyes. Perhaps you can get hold of one or ask your physician or eye doctor to let you try it on him/her. > > One other time that one sees the inside of the eye is when you get red-eye in a photograph. What you see hereis the reflection off the retina of the rhodopsin, the pink colored photopigment in the rod photoreceptors. now i am confused. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [March 14, 2003, 6:30am UTC](https://boards.straightdope.com/t/causes-of-and-avoiding-red-eye-in-photos/161076/22 "2003-03-14T06:30:04Z")
I don’t think your posts and the others are mutually exclusive **antechinus** , it would seem that rhodopsin is what gives the retina the pink/red colour. ---
**Author:** ![ataraxy22](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ataraxy22/32/307_2.png) [@ataraxy22](https://boards.straightdope.com/u/ataraxy22)\ **Post date:** [March 14, 2003, 7:21am UTC](https://boards.straightdope.com/t/causes-of-and-avoiding-red-eye-in-photos/161076/23 "2003-03-14T07:21:01Z")
> [@](#): > > \*Originally posted by antechinus \* > \*\*I always thought it was because of absorption of part of the flash light by rhodopsin - reflecting red. > > If a pre flash is used is ‘uses up’ the rhodopsin - converts it from trans to cis configuration (or is it the other way around). \*\* Other way around…it goes from an 11-cis to an all trans conformation when exposed to light. I always thought that the pre-flash was to cause the pupil to shrink and therby make any redeye minimal FWIW, rhodopsin is red before bleaching upon light exposure. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [March 14, 2003, 12:49pm UTC](https://boards.straightdope.com/t/causes-of-and-avoiding-red-eye-in-photos/161076/24 "2003-03-14T12:49:33Z")
**ticker** is right. Off-camera flash is the best way to solve red-eye AND the best way to start taking GOOD flashed pictures. Flash can look great if you know how to use it, and normally that starts by taking the flash off the camera and connecting it to the camera via a sync chord. Hold the flash a foot to the left or right of the camera (or have someone assist you) and you’re pictures won’t look so flat and you won’t get red eye. If you want to get less harsh lighting, use an umbrella, a soft-box or a portable bounce board. The last is the most convenient of the bunch. Or bounce of the ceiling. Use bounce flash whenever you have the opportunity. You’ll get much more flattering lighting. (Unless you want to go for the harsh frontal-lighting style. It can look cool.) The key to bounce flash is to have a ceiling that’s not too high (maybe 3 or 4 meters high…depends on the strength of your flash unit) and it should be white. (Doesn’t leave a color cast and reflects well.) [Previous page](https://boards.straightdope.com/t/causes-of-and-avoiding-red-eye-in-photos/161076.md?page=1)