A6500 in Auto ISO Mode

[Gary Terry]

I set my wife's A6500 in Auto ISO mode in sunny daytime venue, indoors with lots of windows. For some reason, some of the images were exposed at ISO 250, ISO 400 & with no change of lighting, jumped to ISO 40,000. Thus making the images very grainy. Can someone suggest why the large jump in ISO. ISO 1600 would have been more than enough to properly expose the images. Needless to say, I will never use that setting again. 

[Username]

Maybe spot metering ?

[Guest Jaf-Photo]

You could probably use Auto ISO again, if you set minimum and maximum ISO to reasonable levels. For instance, you could have set minimum to 100 and maximum to 1600, if you felt that would have been adequate.