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Old Jul 30, 2007, 12:19 AM   #1
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Hello...at the moment I'm using Speedlite 430EX on my canon 400D. I also whack on a diffuser because my friend says it helps to reduce the harsh lighting that you sometimes get from direct flash.

However, I find that getting the correct exposure with flash is very tricky. I want to take candid shots, so I need to get it right the first time and avoid fiddling around with the flash exposure settings.

Can someone offer advice on how to get more consistent results with the exposure when using flash?
And if I use a diffuser indoors, should I still point the flash towards the ceiling to bounce it or should I point the flash directly at the subject?

Thanks
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Old Jul 30, 2007, 9:08 AM   #2
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A diffuser already "reduces" the light output by diffusing it so you should not have to bounce (actually a diffuser is used in case you can't bounce off high ceiling) - If you do bounce the flash with a diffuser on you might not have enought light left in some cases to reflect back from the walls.

You also didn't say which mode your camera was in: The camera's manual mode is the only mode where one has control over the flash automatically...

Have you try to do a Flash Exposure Lock (FEL) using the AEL button?
-> Instead of evaluating the whole scene the exposure is locked in the area of interest only. This does emit a pre-flash, but you can be really quick in following up with a shutter release
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Old Jul 30, 2007, 6:31 PM   #3
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your flash allready has a diffuser built into it and when used the camera automatically adjusts for it. do not use it over 15 feet away and do not use it when you bounce the flash. when bouncing you can do it of off a ceiling or wall just make sure they are white and not very far away. just practice and you will get it.good luck.
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Old Jul 30, 2007, 6:55 PM   #4
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If you set your camera on manual, and the flash on auto, you should get good exposures. Try to keep the shutter speed between 1/60 and 1/250sec, (or whatever max flash sync is for your model). Generally speaking, slower shutter speeds will give more light on the bg, and faster shutter speeds will make the bg darker. Try using an f-stop between f4 and f8 to start. Experiment before you are in that situation again. Digital shots don't cost anything. :blah:
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Old Jul 31, 2007, 1:10 AM   #5
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Thanks for the advice everyone.

Ok, but I thought even in Av or Tv mode, you can adjust the flash by the flash exposure menu?

So if a diffuser reduces the light output, should I increase the flash exposure setting? Or does this beat the whole purpose of putting on a diffuser?


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Old Jul 31, 2007, 5:55 AM   #6
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Your flash measures light on the subject, so you don't have to compensate for the diffuser. However, your max shooting distance will be reduced.
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Old Aug 1, 2007, 7:55 AM   #7
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how much is it reduced to?
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Old Aug 1, 2007, 10:19 AM   #8
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jaykobe wrote:
Quote:
how much is it reduced to?
According to the 430EX manual, when you use the built-in wide angle diffuser the Guide Number is reduced to 11 in meter (or 36 in ft) @ ISO 100
-> @ f/2.8 you have about 3.92 meters max. to work with (i.e. 11/2.8 ) :idea:
... without the internal diffuser you have at least double that distance (@ ISO 100)


Of course with an external "whack on" diffuser anything is then up for grab... :lol: :-) :G





jaykobe wrote:
Quote:
Ok, but I thought even in Av or Tv mode, you can adjust the flash by the flash exposure menu?
You can adjust the flash exposure in any mode including Manual - What you can't control is the camera in Av, Tv or P: Like it has a mind on its own when it tries to expose for a fill with its evaluative metering... Problem is you don't know what the camera is "evaluating"

When you do an FEL lock the metering is changed to partial instead so the exposure becomes more selective and with the manual mode you prevent the camera from straying away from the selected shutter and aperture - i.e. the only variable now is how much the automatic flash will put out to balance the scene... which you can still vary with the flash exposure menu!
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