weird...auto ISO change?

Either I pushed a sequence of buttons in the field and totally forgot, did it on accident, or my camera changed ISO settings automatically halfway through my shoot...

My first half photos are ISO 200 and 400....as set by me on purpose.

Now I'm back home in the middle of PP work and noticed all of a sudden there is a lot of noise in the latter half of my pics....I couldn't figure it out, as I swear I didn't change the ISO at all during the shoot, except once...to go from 200 to 400.

But reading the data, these were shot on H, or 3200 ISO...

I am nearly positive I didn't change the ISO to H....not on purpose anyway...

Can/would my 300D change ISO on me automatically somehow? Or are we looking at operator error here?

Thanks, bummed...as a few of the 3200 shots came out perfect except for the high ISO which makes them tossers for the most part.



EDIT, camera set to Av mode...as always

My only guess is you used some of the "basic zones" using up to ISO 400, then went to one of the "creative zones" and had a higher ISO setting still set from an earlier shoot.

nah...Av is the only mode I have ever used...

I am thinking I know what may have happened...I was changing my aperture constantly out there, trying to learn with my 50mm (I'm quite new)...I think when I changed from ISO 200-400 I may have changed it but didn't hit the ISO button again to confirm it...or pressed ISO by accident and then changed my aperture...but actually changed the ISO instead...

I'm sure that's what happened...unless the hack makes a button "auto H ISO" or something and I just don't know about it....doubtful...

Unless you have a Nikon D200, I suspect you mistakenly hit a wrong button.