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I am interested whether the position of the flash at the three examples of point and shoot cameras below would avoid or at least decrease the red eye effect. Or do you feel that all flashes are still close enough to the lens to cause red eye?

The cameras are just used as examples!

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  • \$\begingroup\$ don't see any relationship of the cameras with the question... :( \$\endgroup\$
    – kmonsoor
    Apr 3, 2014 at 16:26
  • \$\begingroup\$ it's about the flash of these cameras ;) \$\endgroup\$
    – Morpho
    Apr 3, 2014 at 16:55
  • \$\begingroup\$ i see. i got it \$\endgroup\$
    – kmonsoor
    Apr 3, 2014 at 16:58

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It depends on the distance at which the picture is taken. According to Wikipedia:

If direct flash must be used, a good rule of thumb is to separate the flash from the lens by 1/20 of the distance of the camera to the subject. For example, if the subject is 2 meters (6 feet) away, the flash head should be at least 10 cm (4 inches) away from the lens.

2 meters is already pretty close for a portrait shot, and those cameras look like the distance between flash and lens is less than 10cm, so they'll probably still cause red eyes for all but extremely close shots.

To be exact, in order to avoid red eyes, you want the angle of reflection from the flash to the lens via the eye to be more than 2.5 degrees, which means an angular distance of at least 5 degrees:

enter image description here

But nowadays most cameras can emit a pre-flash that causes pupils to contract (reducing the effect) or even automatically remove red eyes in post-processing.

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  • \$\begingroup\$ How should I measure the distance, the 10cm in this case? Horizontally or vertically? \$\endgroup\$
    – Morpho
    Apr 3, 2014 at 12:24
  • \$\begingroup\$ @Morpho: I'd say that it should be measured directly, diagonally, if you will, since the eye's pupil is round. \$\endgroup\$ Apr 3, 2014 at 12:27
  • \$\begingroup\$ By diagonally do you mean from the lens to the flash diagonally? \$\endgroup\$
    – Morpho
    Apr 3, 2014 at 12:33
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    \$\begingroup\$ Morpho: see updated answer \$\endgroup\$ Apr 3, 2014 at 13:29
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    \$\begingroup\$ @Morpho: correct \$\endgroup\$ Apr 3, 2014 at 14:03

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