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06-16-2011, 06:15 PM   #16
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Couldn't get the image to show here so I'm giving a link to my google album.
https://picasaweb.google.com/100157556631529141758/Test?feat=directlink

I did the same thing jatrax did, which is what I've been talking about, but my image comes out correctly exposed as though it's at 1.4, no matter what I set the aperture at. Everything functions exactly as it should in Manual as well.

You can see the images at my link.


Last edited by beesmyer; 06-16-2011 at 06:28 PM. Reason: fixing link
06-16-2011, 08:21 PM   #17
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QuoteOriginally posted by beesmyer Quote
Couldn't get the image to show here so I'm giving a link to my google album.
https://picasaweb.google.com/100157556631529141758/Test?feat=directlink

I did the same thing jatrax did, which is what I've been talking about, but my image comes out correctly exposed as though it's at 1.4, no matter what I set the aperture at. Everything functions exactly as it should in Manual as well.

You can see the images at my link.
This is as expected. Your f22 on P was f1.4 on Av.
Doesn't explain why jatrax had underexposure though. Only thing I can think of is maybe a non-conductive base.
06-17-2011, 11:31 AM   #18
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OK, try this:

1) Put camera in Av mode aperture at f1.4 and point at a target. Write down what the speed is on the LCD.
2) Change the camera to 'M' mode, change the speed to something silly like 1sec. Point the camera at the same target and hit the green button. You should get the same speed or very close to what you wrote down before.
3) Put camera in Av mode set aperture to F22 (or whatever is the smallest). Point at the same target and record what speed the camera wants to use. It should be the same as above.
4) Change the camera to 'M' mode (f/22 or smallest). Point at the same target and hit the green button. You should get a very different speed, much longer than before.

In 1 & 2 you are metering at f1.4 in both M and Av so you get the same reading.
In 3 & 4 you are metering at f1.4 in Av and at f/22 in M so you get different readings.

You are getting correctly exposed pictures because the camera is adjusting the speed for you in Av to expose correctly at f1.4. Your test shots are indoors in relatively dim light so it is within the camera's capability. Try this test outdoors in bright light and you will see that the camera cannot adjust enough, it will go to 1/6000th and then flash over load.
06-17-2011, 12:46 PM   #19
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QuoteOriginally posted by jatrax Quote
OK, try this:

1) Put camera in Av mode aperture at f1.4 and point at a target. Write down what the speed is on the LCD.
2) Change the camera to 'M' mode, change the speed to something silly like 1sec. Point the camera at the same target and hit the green button. You should get the same speed or very close to what you wrote down before.
3) Put camera in Av mode set aperture to F22 (or whatever is the smallest). Point at the same target and record what speed the camera wants to use. It should be the same as above.
4) Change the camera to 'M' mode (f/22 or smallest). Point at the same target and hit the green button. You should get a very different speed, much longer than before.

In 1 & 2 you are metering at f1.4 in both M and Av so you get the same reading.
In 3 & 4 you are metering at f1.4 in Av and at f/22 in M so you get different readings.

You are getting correctly exposed pictures because the camera is adjusting the speed for you in Av to expose correctly at f1.4. Your test shots are indoors in relatively dim light so it is within the camera's capability. Try this test outdoors in bright light and you will see that the camera cannot adjust enough, it will go to 1/6000th and then flash over load.
This is exactly what I found which lead me to realizing I wasn't using it right and I discovered proper M mode stop down metering. So my question is this... When in AV and the aperture ring set at f22, and the ambient light isnt extremely bright like you mentioned.... How does it take a properly exposed image for a stop of 1.4? Remember, the aperture is stopping down to f22 when I release the shutter. Does it take the picture only when it opens back up? Does it take it before it closes? Everything I've read from people tells me it will be underexposed.

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