my xt outperforms my xsi brightness of image

I took about 60 shots with each on a tripod at night indoors using the same prime and the xt would gather more light using different f stop ranges, the xsi did focus better. Sometimes the xt would hunt a little more than the xsi. Just wondering if i got a bad copy or is it standard deal that the xt gathers more light?
thanks

You sure that the XT didn't meter hotter? I've had both and it seemed that the XT over exposed by about 2/3 stops and the XTi under exposed by about 1/3 stop but if you manually set the ISO, speed, aperture, it was pretty much the same.

Can you post two pics with EXIF data intact showing the difference.

burb72 wrote in post #6580340
I took about 60 shots with each on a tripod at night indoors using the same prime and the xt would gather more light using different f stop ranges, the xsi did focus better. Sometimes the xt would hunt a little more than the xsi. Just wondering if i got a bad copy or is it standard deal that the xt gathers more light?
thanks

I'm not sure if this applies to the xt/xsi, but I believe at one point Canon was understating their ISO values by about 1/3 of a stop (ISO100 was really ISO125 equivilant and so on). This was around the 20D/30D timeframe. On the more recent cameras they corrected this so ISO100 in camera is now really closer to the ISO100 standard. This may be what you are seeing.

Yes, it's well documented that all canon cameras up to the 30d/5d were underrated by a third of a stop. when the camera is at iso 800, it actually is as bright as an iso 1000 camera should be. It's not that the XSi is darker, it's that the XT is brighter. The hunting is normal, XSi has the same AF system as the 20d, the XT only has that of the 10d.

I used a 1.8 prime, had both set at iso100, both set to same shutter speed, changed f stops. Tested at 1.8 and also at 2?, 4? and started to change iso and speed. At every same setting, the xt produced a brighter image. Thanks for your help, question answered. If my xt could focus better might keep the xt.
mike

Both are set at iso100. Answer solved. As I said before, the sensor is more sensitive than it should by a third of a stop. The metering system is the same, so changing the setting for both won't help.