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Old May 18, 2008, 8:42 PM   #1
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I recently had the Kodak Z650, turned it on and checked out,started to takea picture, and WHOA! GREEN?! I don't think i've ever used a camera with a green a/f illuminator, I thought it was all orange!.....so, what else is out there, and which color is best?
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Old May 21, 2008, 11:16 AM   #2
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My Z612 is a bluish white and I do know that some cameras use a yellowish white color. I have seen nothing to indicate that the choice of LED illuminator color has anything to do with the low light focusing capability of a particular camera.

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Old May 21, 2008, 12:08 PM   #3
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My Sony A700 projects a pattern with both thinner and wider vertical red lines. It's probably optimized specifically for the Autofocus Sensor Asembly being used in this camera body.

A non-DSLR model uses a contrast detection based system instead, with the camera's main imaging sensor used for Autofocus (versus a separate sensor for Autofocus in a DSLR model).

Sony started using laser based AF assist that projects a red pattern in some non-DSLR models a while back. So, a pattern approach would work well for a non-DSLR model, too. A pattern easily distinquishable so that the sensor can see contrast is what you want (because some subjects may not have much contrast for the camera to see and this techique provides some. Here's what you'll find if you read through our Sony DSC-F717 review:
The F717 features high-speed scan autofocus and a "hologram" focusing assist device to insure properly focused pictures no matter what the light levels are. This new autofocus system uses a Class 1 laser to paint a grid pattern on the subject and is perfectly safe, even when aimed directly at someone's eyes. I found it nearly impossible to "fool" the AF, the only out of focus pictures I ever got were when I was using the manual focus mode. The maximum range of the laser-assisted AF system is 4.5m

This is what it looks like:

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Old May 21, 2008, 8:30 PM   #4
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Green light could very well be the best color to use for autofocus. The Bayer pattern sensors have green pixels for half the pixels, so this should give you the most sensitivity and best contrast, as opposed to either red or blue. Just a guess, though.

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