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 Attention to Canon 400D Owner..., AF-Assist Beam...Question

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calvin_gsc
post Jul 30 2007, 08:06 PM

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QUOTE(sweesin82 @ Jul 30 2007, 07:53 PM)
Hi..wanna ask whether CAnon 400d has a AF-Assist beam or not like other camera??

I try to use 400D in with flash in low-lighting condition...it will have a intermittent flash for few times when i half press the shutter button....not beaming a light out..

is this call Flash Strobe???like too consuming the battery lo....

Is this normal for every camera..??

Hope u all 400D member can help me out ya..

thankz a lot lot...
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QUOTE
While that circular lamp to the upper-left of the lens mount looks like an AF-assist lamp, it's not. Instead, it's used as the visual countdown for the self-timer, as well as for redeye reduction. Like most of Canon's D-SLRs the XTi uses the pop-up flash as a focusing aid in low light. If you want the benefits of AF-assist but don't want a flash shot, then just let the camera lock focus and lower the flash


http://www.dcresource.com/reviews/canon/di...iew/index.shtml

There isn't any AF assist lamp, it uses the flash strobe as stated above.
calvin_gsc
post Jul 30 2007, 09:59 PM

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QUOTE(kenlui @ Jul 30 2007, 09:45 PM)
@sweesin82
It's normal, dont worry. I prefer those old school days canon film body when they use a separate small lamp to assist in AF. If i'm using an external flash the build in camera flash cant be used in assisting AF.
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The external flash has AF assist beam right? if using 430ex/580exII

QUOTE(sweesin82 @ Jul 30 2007, 09:48 PM)
yaya...i prefer the small lamp oso like in the Nikon Camera..an orange light for the AF-Assit Beam...

wat for using so high flash to assist the AF o....only use in very black environment lo...

if i wanna shoot without flash then how can i use the AF-assist??

Canon does not have flash option le..like nikon got slow sync, red eye (select inside menu only), rear flash and so on....

any opnion on this??
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Well, the only alternative you have is to get a small led torch light and attach it to your cam with velcro or something. When you take photos in low light, turn on the small led torch light, and it will help you focus.
calvin_gsc
post Jul 31 2007, 07:38 AM

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QUOTE(AlamakLor @ Jul 31 2007, 01:07 AM)
The pre-flash will also help reduce red eye smile.gif if you dont like the stupid flash, try to find yourself an infrared flash light to help AF in low light, your subject wont see anything besides you pointing a "no battery" flash light at them tongue.gif
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The IR flashlight ray can be detected by the camera for AF but not the human eye?
calvin_gsc
post Jul 31 2007, 12:24 PM

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QUOTE(AlamakLor @ Jul 31 2007, 12:20 PM)
yup, IR can't be detected by eyes, but the camera will see it. Never seen this sort of things in science centre? lol
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I never seen it in science center. Which science center? All science center in the world also got? tongue.gif

But you can easily see IR ray by using a digital camera on your mobile phone, turn on the camera, face it to the remote control IR point, and you will be able to see a bring light from the remote when you press a button.

I thought cameras would need a visible light like the light on the D80 to assist in AF. Cause if invisible light ray like IR, how would it be able to illuminate the subject/object you are shooting? blink.gif

Then how come all AF lamps on camera are bright lit, why don't they just use IR?

This post has been edited by calvin_gsc: Jul 31 2007, 12:45 PM
calvin_gsc
post Jul 31 2007, 12:47 PM

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QUOTE(AlamakLor @ Jul 31 2007, 12:44 PM)
Just because the light can't be seen by bare eyes doesn't mean the camera can't see it tongue.gif

I suppose why camera manufacturers don't use IR is because IR leds dont have enough intensity compared to xeon bubs. Or at least they cannot insert enough leds in the tiny hole to get adequate intensity.

CCTV is well known to use IR to light up subjects in order to help the camera to focus:
user posted image
Have you seen any CCTV with big xeon/halogen lamps to help it focus? laugh.gif
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Are there any digital camera at all that uses IR for AF? laugh.gif

Any brands or model?

Is CCTV = Digital camera? No right? doh.gif

We're discussing how it'd help a digital camera right? More specifically in this case, a Canon 400D dslr.

This post has been edited by calvin_gsc: Jul 31 2007, 12:53 PM
calvin_gsc
post Jul 31 2007, 01:07 PM

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QUOTE(AlamakLor @ Jul 31 2007, 12:59 PM)
I was just giving an example of IR used to help camera sees in the dark without actually illuminating the subject with lights that can be seen by bare eyes. It has nothing to do with whether the camera is digital slr, or digital video cam.

IIRC the canon ex flashes uses IR to AF assist. Some people are very sensitive to pre-flashes *closed eyes before the exposure is made*, using IR to help focus would avoid this sort of problem. You can get an led torch, gut the leds out and replace them with high intensity IR leds smile.gif

http://www.dpreview.com/learn/?/Glossary/C...ist_lamp_01.htm
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I wonder why they never incorporate IR for AF into the digi cams or external flashes if it's effective. Maybe it's not... hmm.gif

This post has been edited by calvin_gsc: Jul 31 2007, 01:07 PM
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