Correct exposure when using external metering of 580EX II

[csphua]

Hi all,


I read from many sources that auto external metering of 580EX II will always under expose. Is there a way to correct this using manual external metering?

Let's say if I shoot with ISO 400, can i set the manual external metering to ISO 200 and get correct exposure?


Thank you.

[Sheiky]

Hey,


I'm not really sure I understand your question. I can say that you can adjust your external flash(mounted on camera) with -2 exp to +2 exposure and retain the metering from the camera. If the 580 always underexposes, you could adjust it very easily by setting the exposure compensation to a standard where it doesn't underexpose.


I hope I helped you out a bit...


Jan

[peety3]

Do you mean with the little sensor on the front of the 580? Why would you want to do that instead of ETTL?

[scalesusa]

Heve you read this? [url="http://www.usa.canon.com/dlc/controller?act=GetArticleAct&articleID=946]http://www.usa.canon.com/dlc/controller?act=GetArticleAct&articleID=946[/url]





Depending on the camera model, external metering should work fine, but you need to experiment to learn the limitations.





I think this paragraph may answer your question.





Deliberately under- or over-exposing flash in External metering: Manual mode


If you want flash exposure to intentionally be greater or less, you have to do one of two things: set a different camera lens aperture than the one you’ve set on the back of the flash, or change the camera’s ISO to a different value than the one you reported to the speedlite.
In other words, if you take a picture with all flash settings matching the camera settings, and the first shot looks too dark, you can brighten flash exposure by:

1) Setting a wider lens aperture than what you set on the flash <span id="__firefox-findbar-search-id" style="display: inline; color: black; padding: 0pt;"](example: flash says f/8; you set the camera to f/5.6 to brighten exposure one stop).
2) Raise the camera&rsquo;s actual ISO above what you&rsquo;ve set on the flash <span id="__firefox-findbar-search-id" style="display: inline; color: black; padding: 0pt;"](again, to lighten the exposure, if the flash&rsquo;s LCD panel is set to ISO 100, setting the camera&rsquo;s ISO to 250 would deliberately over-expose by 1-1/3 stops).