Is use of red eye reduction a good idea?

[travelwalk]

I've had the red eye reduction option normally turned on in my Canon S3IS for some time. Never had an obvious problem, but can't say that it's obviously fixed any potential problems either.

However, after experimenting with the red eye tool in Photoshop recently and getting some occasionally strange results, I began to wonder - Is it really a good idea leaving the red eye reduction on in this camera, or in any camera, a good idea?

If red eye reduction can cause some odd artifacts in Photoshop, couldn't it sometimes cause odd artifacts in a camera? I assume it's just software in camera that's doing the red eye correction.

If there's any chance of error in the red eye correction, it would make sense to do it in Photoshop where you can look at the difference and undo the change if you didn't like it.

Or is there something different about in-camera red eye reduction that makes it unlikely to ever make a mistake?

 

[PC Wheeler]

I never it while shooting but clean it up in pp.

--
Phil .. Pany FZ18, SD700IS, EOS 300D & 20D; Canon S3 IS; Fuji F20 & F31fd.
http://www.pbase.com/phil_wheeler
http://www.flickr.com/photos/phil_ox/

 

[jimjim2111]

I've had the red eye reduction option normally turned on in my Canon
S3IS for some time.

Maybe the s3 is different from my sd850 but in my camera I have 2 red eye features. Turning "Red Eye" on in the menu sets the camera to shine the focus assist (bright orange) light just ahead of taking the picture. This makes the subject's pupils react and that stops red eye, in theory.

I don't use this feature as it's a blinding light, a bit unsociable, and it delays the pic I reckon.

The other feature is the "red eye correction" where you can look at photo (in camera) and correct red eye. It gives the option to keep the original and I notice it saves the corrected image in a file 2/3rds the size of the original. I use that one sometimes but I always keep the original.

 

[mamallama]

I've had the red eye reduction option normally turned on in my Canon
S3IS for some time. Never had an obvious problem, but can't say that
it's obviously fixed any potential problems either.

However, after experimenting with the red eye tool in Photoshop
recently and getting some occasionally strange results, I began to
wonder - Is it really a good idea leaving the red eye reduction on in
this camera, or in any camera, a good idea?

If red eye reduction can cause some odd artifacts in Photoshop,
couldn't it sometimes cause odd artifacts in a camera? I assume it's
just software in camera that's doing the red eye correction.

I think you are confusing red eye reduction with red eye correction.

Reduction is a hardware function that pre-flashes t he actual flash, hoping to somehow get the subject's pupil to close thereby reducing red eye. It is not effective and only serves to increase the shutter lag. It's a total waste, a marketing gimmick only. Leave it OFF.

Correction is a software function that you can do in playback after the image is taken. I don't think your S3 has it. It fills in the red with a dark color and if not matched with the subject properly, it can look phony. So can the correction function in some post processing software, which sounds like your version of PhotoShop does.

Some advanced red eye correction software give complete control and allows you match the subject exactly. One that I have that allows this fine control is Corel Paint Shop Pro XI. You not only can match the color you can control the transparency so you just don't get a black spot.

If there's any chance of error in the red eye correction, it would
make sense to do it in Photoshop where you can look at the difference
and undo the change if you didn't like it.

Or is there something different about in-camera red eye reduction
that makes it unlikely to ever make a mistake?

I've never used in-camera correction (I believe you mean), but some otherwise very capable post processing software don't allow you to do a good job as I stated above.

--mamallama

 

[Mike G Lee]

If in-camera red eye reduction doesn't work satisfactorily for you, and all you need to do in post-processing is remove that red eye, then use Red-e-Rem http://www.geocities.com/rederemhome/

It will remove the red eye (and very well too) without recompressing the entire image, thus preserving the original image quality.
--
creator of the Lossless JPEG Toolbox
http://losslessjpegtoolbox.wordpress.com

 

[EricDP]

It will remove the red eye (and very well too) without recompressing
the entire image, thus preserving the original image quality.

If it alters the image, it recompresses it when it is saved. Since jpeg is lossy, there will be some lost quality - unless it is saving it as a tiff or some other lossless format. There is no way to alter a jpeg and save it as jpeg without recompressing it.

 

[mamallama]

It will remove the red eye (and very well too) without recompressing
the entire image, thus preserving the original image quality.

If it alters the image, it recompresses it when it is saved. Since
jpeg is lossy, there will be some lost quality - unless it is saving
it as a tiff or some other lossless format. There is no way to alter
a jpeg and save it as jpeg without recompressing it.

If I read Mike G Lee correctly, he said "without recompressing the entire image" to mean only that area changed, i.e., the eye is recompressed. Maybe Mike can clarify.

--mamallama

 

[RedFox88]

It's just how the back of people's eyes reflect light to the camera. I have dealt with fixing red eye in pictures from many different P&S models that often have odd looking eye reflections.

 

[Mike G Lee]

Lossless JPEG editing is (unfortunately) still a relatively little understood technique, even in hobbyist or (semi) professional circles, like those of the dpreview forums. Many modifications can be done to a JPEG without recompressing portions unchanged in the editing process. Actually, very few editing tools exist which permit these lossless modifications. The most common lossless functions that photographers are generally aware of are rotation and cropping, but numerous other modifications can be performed on a JPEG without degrading unchanged portions and putting the entire image through a generational loss in quality.

It is absolutely possible to edit a JPEG image, as one would do in Adobe Photoshop, like cloning or localized retouching, and then save the image with only those regions which were changed being recompressed, preserving the original quality of the majority of the image. Developing such lossless tools is a great interest of mine, as we live in a JPEG world and I am personally not one to be content with compromising my images unless absolutely necessary.

There are some very nice (and free) lossless editing tools available from various sources. I am adding new tools on my website as often as I come up with new ideas which I can develop into working applications. I am working on several new ones at this time. Your comments will prompt me to create some links on my website to direct users to the various lossless editing tools available today. Red-e-Rem is good lossless freeware for the removal of red eye.

I will leak this bit of information - there will soon be released (by another author) that Photoshop-like editing software that will perform lossless JPEG editing by default - and it is expected to be released as freeware. The future is looking bright for those who shoot JPEG.
--
creator of the Lossless JPEG Toolbox
http://losslessjpegtoolbox.wordpress.com

 

[EricDP]

I stand corrected...

 

[New Photog 2008]

I read somewhere that the shorter the distance between the flash and the camera lens, the more likely red-eye will occur.

Since moving to the Canon S5 and an external flash, I have had no problems with red-eye at all - not one single instance. Maybe there is truth to what I read because the distance from flash to lens is now substantially greater than when using the onboard flash.

 

[mamallama]

I read somewhere that the shorter the distance between the flash and
the camera lens, the more likely red-eye will occur.

Since moving to the Canon S5 and an external flash, I have had no
problems with red-eye at all - not one single instance. Maybe there
is truth to what I read because the distance from flash to lens is
now substantially greater than when using the onboard flash.

Actually, it's the angle subtended by the lens and the flash as viewed from the eye. At short subject-to-camera distances the angle with the external flash is greater. But as that distance increases red-eye is more likely again. With the higher power of the external you will likely be shooting at greater distances also.

--mamallama

 

[RedFox88]

I read somewhere that the shorter the distance between the flash and
the camera lens, the more likely red-eye will occur.

This is why professional photographers use a flash bracket for portraits and weddings. This gets the external flash even farther away from the camera. But I hardly get red eye with my external flash mounted onto my 5D.

 

[glenncombs]

mamallama,

I think I will turn off red eye reduction for our Canon cameras. I still have to do some post processing now and then, anyway. It's probably not helping much.

If any manufacturer does release a full featured camera that absolutely, automatically removes/prevents red-eye in human photos, it's going to sell like crazy. Until then, we'll just hang on to our older Canon's. The image resolution is good enough, and I love the smaller file sizes.

Glenn
--
Alexander...our wild child



Canon S2, A610

 

[fionat]

I have a G9, quite new, but I have found that the red eye reduction doesn't really live up to expectations. On every day I take photos, I know that some will need photoshopping to get rid of red eye. I do love the camera, it's the best one I've had since the G1 LOL!! I am a canon baby, sorry

 

[New Photog 2008]

Actually, it's the angle subtended by the lens and the flash as
viewed from the eye.

--mamallama

Got the following info from bytecamera.com:

"the reflection angle of the flash plays a vital role, as the light is recoiled back to the digital camera and the closer the incident light beam is to this reflected light beam, the greater becomes the red eye effect.

To prevent this instruments such as flash brackets are useful to make the flash a bit removed from the propinquity of the lens.

It can be noted here that the only important thing is that the users must ensure that the proper fixing of the angle between the flash beam and the lens axis. The general rule here is that the photographer must keep the angle wide enough that the light beam from the flash does not reflect off the retina of the person being photographed and comes right back into the digital camera lens.

Other factors influencing the red eye are the level of ambient light during the time when the photograph is being taken and how near the flash light is to the lens. The rule of thumb comes out that the brighter the ambient light; the lesser is the effect of red eyes, everything else being one and the same. As the flashlight goes farther from the lens, the fewer becomes the effect of red eyes, everything else being one and the same again. Thus the key idea is that red eye is not caused if the ambient light is comparatively high. And it does have a significant effect if the shooting area is dark. Many digital cameras have built in features for anti red eye that is used to reduce red eye when taking a picture of a person looking straight at the camera also. But manually, the best red eye reduction can be obtained with the help of an external flash as described."

 

[Devedander]

I have found that looking not directly at the lense helps avoid red eye... I find when posing people with a flash that if I try to direct their focus to my hand or something just off to the side of the lense I get fewer red eyes.

this involves cooperative subjects though

 

[mamallama]

I have found that looking not directly at the lense helps avoid red
eye... I find when posing people with a flash that if I try to direct
their focus to my hand or something just off to the side of the lense
I get fewer red eyes.

this involves cooperative subjects though

Yes, that is a good tip; sort of like directing the retina reflection away from the lens. But if overdone it looks like subject is strangely disinterested.

For posed situations, another tip is to ask the posing subjects to look at a bright object like a window or a lamp for a few seconds. This closes the pupils and reduces the reflections from the retina, exactly what the red-eye preflash attempts to do but, IMO, more effectively. Works somewhat with dark complexion people with dark irises, but for those with lighter complexion and more transparent blue irises, nothing seems to work.

--mamallama

 

[New Photog 2008]

Good tips. Thanks Develander and mamallama.