Camera Labs

Hey guys/gals! I've got a new Xsi, and I have a question regarding the automatic exposure compensation.

I took two pictures of the same stationary object, in the same lighting. In "P" mode, the camera set my shutter to 1/60 and the apeture to f/4. I immeadiately took the second pic in "Av" mode and set a matching apeture of f/4. But this time the camera set the shutter to 0.3 seconds. All other settings remained the same: ISO, Metering Mode, WB, etc.

With the exposure level the same, shouldn't the shutter speeds be identical in both situations? What am I missing?

Please be gentle.

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Canon XSi/450D, Canon EF-S 18-55 IS, Nifty Fifty, 24-105L, 70-200mm f/2.8 IS USM, 430EX II Speedlite

Hi,
I am also a beginner. I suppose that, maybe the computer's calculation get a different result when you did it with Av.

I just got my XSi too. We are in the same boat:D

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Canon 450D
EF-S 18-55mm IS

FlickR

Well, tried to do some research, but I still can't find an explanation.

I've experimented with different situations, but the exposure settings are always different. It's crazy!

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Canon XSi/450D, Canon EF-S 18-55 IS, Nifty Fifty, 24-105L, 70-200mm f/2.8 IS USM, 430EX II Speedlite

Perhaps the metering mode was different in P mode than it was in A mode.

By metering a different section of the frame, the camera will change it's exposure.

Best,
-Sean.

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-Blog- || -My Flickr-

Hi folks,

I've moved this thread to the Canon forum since it is a question about the XSi and it's metering. But I've left a "shadow" behind so everyone can find it.

Bob.

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OM-D E-M5 + ED 12-50mm, H-PS14042E, H-F007014E, L-RS014150E, M.ZUIKO DIGITAL 45mm 1:1.8.
Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.