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Old Dec 9, 2006, 6:39 AM   #1
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When I'm in one of the mentioned modes and attempt to use a flash (either pop up or shoe mount) shouldn't my XT set the shutter speed when it ses the flash?

If I select f5.6, my cameraindicated the shutter speed was 1/15 even thought he flash showed charged and ready.

If I know I want to use 5.6, do I need to go to manual and set the shutter and f-stop? The manual is not very clear about these items.

My situation was taking a flash picture of a large group of kids, about 5 packed tightly from front to back and 5 people wide or so. I wanted 5.6 to try and get them all in focus, in P my camera was selecting 2.8 and not allowing the front and back "row" to be in focus.

Sorry to ask yet another rookie question. Thanks!
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Old Dec 9, 2006, 6:51 AM   #2
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In Tv the camera will set the aperture...

In Av the camera will set the shutter; However the camera will expose for a flash fill when the flash is on, so under low-light condition 1/15s is adequate

-> In Manual you can set both the shutter and aperture while the flash will still be on automatic! :idea:
...and this is probably the best mode to use the camera with a flash
(because you can dial-in the fill with the EV-scale -2..-1..v..+1..+2 from the marker below the viewfinder)
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Old Dec 9, 2006, 8:52 AM   #3
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On 'exposing for fill':

In Av or Tv mode, the camera does NOT change either aperture or shutter speed just because you are using a flash. Give it a try - if your camera meters at 1/15 and 2.8 without the flash, it will use the same settings as if the flash was on.

So when you hear people say it will use the flash for fill it basically means the camera is not adjusting exposure at all based on the presence of the flash.

And, you've already seen what P mode tries to do - again, the camera tries to get the best non-flash exposure it can.

As NHL mentioned, this is why it's important to use manual mode when using a flash in low light situations. I would also caution that 5.6 is probably to wide an aperture for a group 5 people deep. You'r in f11 territory there.


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Old Dec 9, 2006, 3:23 PM   #4
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NHL wrote:
Quote:
In Tv the camera will set the aperture...

In Av the camera will set the shutter; However the camera will expose for a flash fill when the flash is on, so under low-light condition 1/15s is adequate

-> In Manual you can set both the shutter and aperture while the flash will still be on automatic! :idea:
...and this is probably the best mode to use the camera with a flash
(because you can dial-in the fill with the EV-scale -2..-1..v..+1..+2 from the marker below the viewfinder)
I appreciate the comments and advice.

When I look at the scale under the viewfinder, it's blinking at the -2 mark. How do I "dial it up" as you mentioned?
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Old Dec 10, 2006, 6:51 AM   #5
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twkenny wrote:
Quote:
When I look at the scale under the viewfinder, it's blinking at the -2 mark. How do I "dial it up" as you mentioned?
If you do nothing the camera will use the flash to 'fill-in' the light to bring the exposure up from -2 to the center v mark (which is the proper exposure). So your resulting image has about 2EV of fill coming from the flash!

Lowering the shutter, opening up the aperture (smaller f-stop), or increasing the ISO will all bring the EV scale to the + right.
Increasing the shutter speed, closing down the aperture or decreasing the ISO will push the EV scale toward the - left side instead
-> What theses permutation do are to allow you to cintrol how dark (more to the left) or bright (more to the right) the background of the image is...
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Old Dec 10, 2006, 9:58 AM   #6
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NHL wrote:
Quote:
twkenny wrote:
Quote:
When I look at the scale under the viewfinder, it's blinking at the -2 mark. How do I "dial it up" as you mentioned?
If you do nothing the camera will use the flash to 'fill-in' the light to bring the exposure up from -2 to the center v mark (which is the proper exposure). So your resulting image has about 2EV of fill coming from the flash!

Lowering the shutter, opening up the aperture (smaller f-stop), or increasing the ISO will all bring the EV scale to the + right.
Increasing the shutter speed, closing down the aperture or decreasing the ISO will push the EV scale toward the - left side instead
-> What theses permutation do are to allow you to cintrol how dark (more to the left) or bright (more to the right) the background of the image is...
Ahhhh.....

It's all (slowly) coming together now!
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