Friday, June 23rd, 2017

Understanding Red-Eye in photos and how it can be prevented

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Why are eyes red in photos?

Red-eye is a phenomenon that happens only when taking photos using a flash. When taking photos in day light or when in high ambient light scenarios people’s eyes look normal. When taking pictures in low ambient light scenarios using a flash the result many times is redness in the people’s eyes.

The reason for the color red is simple – when flash light from the camera hits the eyes it penetrates and is reflected back from the retina. The color of the reflected light is red because the light is actually reflected from the red blood in the retina.

In some scenarios the red-eye is evident while in others it is mild or doesn’t seem to appear at all. One of the main factors for that is the state of the pupils. If the pupils are dilated (for example the pupils dilate in darkness or when drinking alcohol) more light is reflected back from the retina and the eyes in the photo appear redder.

Common way to reduce red-eye

The most commonly used method to reduce red-eye is activating the camera’s built-in red-eye reduction feature. The red-eye reduction feature is very simple yet effective. When turned on the camera shoots a series of pre-flash strobes followed by one more strobe when actually taking the photo. The pre-flash strobes cause the pupils to reduce in size and by the time the photo is taken the pupils are small enough for the eye redness to substantially reduce.

The red-eye reduction feature does what it is supposed to do: reduce the red-eye effect but almost never is it completely prevented. There are many limitations to this feature for example pupils reaction time to light can vary. In addition this feature can have a side-effect that results in photos having people’s eyes closed. The reason is that the pre-flash strobes blind the people and cause them to close their eyes.

Other ways to prevent red-eye

Understanding what causes red-eye helps being more creative in preventing it. Following are some ways to prevent red-eye other than using the built-in camera red-eye reduction feature:

Increasing the light where photos are taken (for example by turning on the lights in a room before taking photos of people) causes people’s pupils to reduce in size and eye redness to reduce.

Point the flash away from the eyes. Since red-eye is caused by flash light reflected from the retina the best way to prevent red-eye would be to eliminate such reflection as much as possible. In most cameras the angle between the flash and the lenses is narrow (this is especially true for built-in flash and pocket cameras) causing most of the flash to bounce back from the retina to the lenses. Increasing the angle (for example by using an external flash) reduces the reflected light. You can also use a bounce flash – by having the flash light bounce off a bright surface (a white wall or a professional reflector) most of the direct reflection from the retina can be eliminated.

Red-eye can also be removed after photos were already taken by using photo processing software on your PC. Most digital cameras include a CD with PC software that embeds this feature. Although this method doesn’t eliminate the red-eye from the source it can result in a practically red-eye free photo. Some software are better than others some are manual while others automatically identify the red-eyes and process that area to revert to normal eye colors.


Digital Photography Success | Web Article Directory

Where there is no vision, the people perish.
Proverbs 29:18

The earth is the LORD’s and everything in it, the world, and all who live in it; for he founded it upon the seas and established it upon the waters.
Psalm 24:1-2

He makes springs pour water into the ravines; it flows between the mountains. They give water to all the beasts of the field; the wild donkeys quench their thirst. The birds of the air nest by the waters; they sing among the branches. He waters the mountains from his upper chambers; the earth is satisfied by the fruit of his work.
Psalm 104:10-13

Look at the birds of the air; they do not sow or reap or store away in barns, and yet your heavenly Father feeds them. Are you not much more valuable than they?
Matthew 6:26

How many are your works, O LORD! In wisdom you made them all; the earth is full of your creatures. There is the sea, vast and spacious, teeming with creatures beyond number living things both large and small.
Psalm 104:24-25

Sometimes I do get to places just when God’s ready to have somebody click the shutter.
Ansel Adams

When you photograph people in colour you photograph their clothes. But when you photograph people in B&W, you photograph their souls!
Ted Grant

While there is perhaps a province in which the photograph can tell us nothing more than what we see with our own eyes, there is another in which it proves to us how little our eyes permit us to see.
Dorothea Lange

When words become unclear, I shall focus with photographs. When images become inadequate, I shall be content with silence.
Ansel Adams

Your first 10,000 photographs are your worst.
Henri Cartier-Bresson

You don’t take a photograph, you make it.
Ansel Adams

Beauty can be seen in all things, seeing and composing the beauty is what separates the snapshot from the photograph.
Matt Hardy

Nothing happens when you sit at home. I always make it a point to carry a camera with me at all times…I just shoot at what interests me at that moment.
Elliott Erwitt

Which of my photographs is my favorite? The one I’m going to take tomorrow.
Imogen Cunningham

You’ve got to push yourself harder. You’ve got to start looking for pictures nobody else could take. You’ve got to take the tools you have and probe deeper.
William Albert Allard

If I saw something in my viewfinder that looked familiar to me, I would do something to shake it up.
Garry Winogrand

I always thought good photos were like good jokes. If you have to explain it, it just isn’t that good.
Anonymous

Twelve significant photographs in any one year is a good crop.
Ansel Adams

It can be a trap of the photographer to think that his or her best pictures were the ones that were hardest to get.
Timothy Allen

 


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