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04-20-2008, 12:39 PM   #31
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But the CameraBright is not infrared. It says it uses white LEDs, which would certainly be visible. It also claims to "reduce redeye, helps compose pictures," etc., which would mean it has to use visible light.

04-20-2008, 11:22 PM   #32
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Take a look of the photos of a Hong Kong guy. He uses a computer game's laser aimer (HK$30 or US$4) as AF assistance light. I have reservation because laser could injure subject's eyesight.

DIY AF Asistance Light

QuoteQuote:
Matters needing attention:
1. Owing to use of the Lazar aimer, I ask respectfully when taking photographs you only aim below the subject's head. Under the usual aperture 5.6, the subject's face is still in focus. Before you take photographs, please remind the subject not to look at the Lazar
2. My original intention of this equipment is to use it in the weak light environment. But afterwards discovered the environment with completely no light it is still possible to focus. The following 4 Test results were all taken in the night, closed the door and turned off the lights.
3. Another interesting recent discovery. You need not look through the ViewFinder to focus. Instead only look at the red spot direction originated from the aimer. This was extremely convenient.
4. Because the laser light beam is stronger, it came out conspicuously in a photo. Therefore let loose the aimer switch after focusing is done. Straight presses down the shutter will do the job. My Test photos below show the red spot of the laser. It is for the purpose of illustration. Under real picture taking, the red spot will not be there after letting loose the aimer switch.

Last edited by dancheng; 04-20-2008 at 11:43 PM.
04-21-2008, 12:16 AM   #33
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i used a normal laser like him and he is right. with a laser, focus is really fast when there is low light or no light. for me the issue is how to stop the laser beam after focus is locked.
i think we can prevent eye damages using a diffuser, imo point and shoot cameras uses laser (with a diffuser, maybe filter in front of it) to focus. p&s cameras are very succesful in low and no light. (for example my fuji f810fd)
04-21-2008, 12:27 AM   #34
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btw this item:
Promaster
doesn't work without a flash.
from dpreview.com paul pasco says:
I have a similar module for Nikon cameras I use with a 5550DX flash unit and no, it doesn't work without the flash on it. It probably needs power from the flash itself because that is where the batteries are.

04-21-2008, 05:53 AM   #35
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QuoteOriginally posted by joefru Quote
But the CameraBright is not infrared. It says it uses white LEDs, which would certainly be visible. It also claims to "reduce redeye, helps compose pictures," etc., which would mean it has to use visible light.

Actually, Halil has confused the issue somewhat by intermixing my infrared suggestion with another person's mention of the CameraBright. The CameraBright is obviously not infrared and I've made no suggested otherwise. My comments have focused solely on the infrared modification to the device I described earlier in this thread. By the way, a laser (such as those being discussed now) is also not infrared, so my comments don't apply to lasers as well. Most camera manufacturers use infrared for focusing assist devices exactly because infrared is mostly outside the visible light spectrum. What little remains in the visible light specturm is eliminated by IR filters over the image sensor.

Actually, it's very simple to convert virtually any light (a flashlight or whatever) into infrared by simply placing an infrared pass filter over the light source. These gel filters are routinely sold by school suppliers, such as Edmund Scientific, to use with optics experiments.

stewart


-

Last edited by stewart_photo; 04-21-2008 at 06:05 AM.
04-21-2008, 12:11 PM   #36
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QuoteOriginally posted by hll Quote
p&s cameras are very succesful in low and no light. (for example my fuji f810fd)
P&S cameras are not good in low light, nor do they have particularly impressive Autofocus. They just fire the flash, and use their large DOF to grab a lot of things within the focus area, due to their small sensor.
04-22-2008, 12:02 AM   #37
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i don't know. but i tested my f810 in low light and no light, its focus speed was really fine for me.
imo it uses a laser pointer and a filter in front of it, like the Honk Kong does
04-22-2008, 12:14 AM   #38
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QuoteOriginally posted by Jonson PL Quote
P&S cameras are not good in low light, nor do they have particularly impressive Autofocus. They just fire the flash, and use their large DOF to grab a lot of things within the focus area, due to their small sensor.
That's totally correct. With my fuji f20, I can correctly focus in pitch black. I tested it in a room so dark that I couldn't see my hand even if I held it in front of my eyes and it focused and took a fine picture.

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