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Old May 21, 2008, 10:22 AM   #11
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Hi NHL It's good to hear from you.
Experimenting with manual settings to minimize the ambient contribution--specifically 1/180 shutter speed and 400 ISO, the aperture blinks at 4.5 (the widest opening for this lens) telling me the shot will be underexposed even though the exposure indicator is set in the middle of the scale. The photo appears to be properly exposed. FYI I was using center weighted metering

Should I just ignore the blinking aperture indication?
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Old May 21, 2008, 3:18 PM   #12
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Again, I'm not that familiar with Canon models. But, the metering is probably only telling you about the ambient light exposure.

So, if it's blinking to let you know the aperture can't go any wider and the photo will be underexposed at the shutter speed/ISO speed being used, the flash is just filling in for the rest.

If the actual exposure looks OK, then the camera is likely providing the correct exposure with the flash to fill. In other words, you're probably just looking at the ambient light portion with the camera's meter. You can then decide the ratio between ambient and flash you want to achieve.

For example, use a 3 stop difference (metering showing the photo is 3 stops underexposed) if you want to keep ambient light from contributing as much, so that the flash is providing most of the light to help separate your subject (with a darker background in lower light). Or, dial your exposure settings back to a 1 or 2 stop difference to let a bit more ambient light in, so that the flash is having less influence with more exposure from other light sources.

Experiment with it. ;-)

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Old May 21, 2008, 5:52 PM   #13
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JimC wrote:
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So, if it's blinking to let you know the aperture can't go any wider and the photo will be underexposed at the shutter speed/ISO speed being used, the flash is just filling in for the rest.
Exactly!

The -2..-1..v..+1..+2 EV scale just tell where the ambient light happened to be and the flash will fill-in the rest automatically to the proper middle of the EV scale:
If you want the background to be brighter you can either lower the shutter, open up the aperture (if you can), or increase the ISO so the marker on the EV scale approaches the middle marker.
Or conversely you can black out the background entirely by increasing the shutter speed, closing down the aperture, or decrease the ISO until the marker go all the way pass the left side of the EV scale

-> The blinking just tell you that the lens setting is outside it's limit (f/4.5), but you can change it to f/5.6 or f/8 for example and the flash will always fill-up the rest (provided you are within its range)



coachjerry wrote:
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... FYI I was using center weighted metering
You can leave the camera in evaluative metering if you want...
Pressing FEL (Flash Exposure Lock) will always use center weighted metering (I use this as a quick overide of the metering without having to change it back and forth)
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Old May 21, 2008, 8:50 PM   #14
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Thanks NHL, JimC and peripatetic

After some experimenting using your suggestions I was able to make significant improvements

NHL that link was extremely helpful in understanding how things work.

Jerry
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Old Jun 11, 2008, 9:28 PM   #15
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when you use the center weighted metering you are going to get a lot of blown out images, specially in darker rooms, the center weighted setting is mainly for if you have no flash and the subject is backlit by a window with the sun or bright lights behind them. it helps lighten the the side of the subject that is closest to you. other wise you would get a silhouette, a friend of mine was having this same problem shooting kickboxing at a night club.
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