T8i ISO too high

[stevet1]

I seem to have developed a problem with my T8i, and I'm not sure what to do about it.

It seems to involve Auto ISO.

When I first turn on my camera and go to take a picture, I half-press the shutter to meter the scene, and set my settings to zero out the exposure. I then fully press the shutter to take the picture. The camera, however, takes a picture that is overexposed.

If I half-press the shutter and take another meter reading a second time with the exact same settings, the camera will take a picture that is more properly exposed.

Here is an example. I used a tripod, so that I didn't inadvertently shift my framing and composition. In both pictures, the settings were 1/500, f/8, ISO 1250.

At this point, I don't know what to except take either two pictures of everything, or stop using Auto ISO. I don't know if I can trust it anymore.

Sometimes that first shot is completely whited out.

Steve Thomas

[SignifDigits]

LOL - just a "feature" then, not a "bug".  That's actually good news-ish, I suppose!

[Waddizzle]

“ Most of the time, I'm using Evaluative Metering, AI Servo with BBF, Single Point Autofocus in Manual Mode. “

Are those photos still inside the canera?  Do they display a locked AF point?

I ask because Evaluative Metering mode biases the exposure to wherever the active and locked AF point is located.  If there isn’t an active and locked SF point, then the exposure is biased to center AF point.

Note , this means when you release the BBF button the AF system goes idle!

One Shot AF locks exposure when focus is locked by a half press.  Exposure remains locked until you either fully press the shutter or release the half press.

Servo AF is not as subtle. It locks exposure when the shutter is fired. But the same caveats regarding the need for an active and locked AF point still applies.