With external flash and shutter fixed at 1/200, why the camera will use ISO 400?


maisatomai

Deregistered
Oct 26, 2006
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#1
With external flash and shutter fixed at 1/200, why the camera will use ISO 400 instead of ISO 100?
 

TKL888

New Member
Dec 20, 2009
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#3
did u set the ISO to Auto?
 

maisatomai

Deregistered
Oct 26, 2006
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#4
Yes, i set it to auto. I use 1/200 as i am shooting at home. My flash is 430ex2 and camera is 600d
 

tecnica

Senior Member
Dec 26, 2004
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#5
what's your aperture?
 

maisatomai

Deregistered
Oct 26, 2006
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#7
I tried 1/60 fixed but because my handholding technique is bad, picture turns out blur. If i never fix the shutter speed via the custom function, my keeper rate will be lower
 

Octarine

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Jan 3, 2008
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Pasir Ris
#8
Yes, i set it to auto. I use 1/200 as i am shooting at home. My flash is 430ex2 and camera is 600d
Which exposure mode are you using? P or AV/Tv/M? Do note that in the exposure metering for flash usage works different for both. This is not flash exposure, but exposure for ambient light. In P, the flash is considered main light. In Av/Tv/M the flash is considered fill light and the ambient light is considered as main light. Metering will read the ambient light first, then fill the foreground / subject with flash.
If you fix the shutter at 1/200 and set a certain aperture (which one, actually?), the camera has only left the Auto ISO to adjust according exposure metering result.
More to read: http://www.photonotes.org/articles/eos-flash/
 

TheoDR

New Member
Oct 19, 2006
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#9
Your cam will go to ISO 400 if it was set to Auto ISO and using built-in/external flash.
 

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