Goofy question... 50D, <200 ISO???

Dumb question For quite some time [~year or so] have been keeping the ISO set on my 50D at 200, unless situations changed requiring a higher ISO,,, never went lower, as seem to recall reading a thread that recommended better IQ for "most" shootings to be at 200, so kept it there and up to 640, and on Auto (when just playing), for the most part. Jump forward to this past weekend and wanted to go lower ISO - and I can't get the ISO lower than 200 unless I'm in C1 or C2 mode [100 - 125 - 160]. So, these three don't exist anywhere else?

You have highlight tone priority enabled. Turn it off and ISO100 will become available.

gjl711 wrote in post #11629076
You have highlight tone priority enabled. Turn it off and ISO100 will become available.

Well,,, I'll be fudged... how / when / why did I do that???

Durn those experiments and buggering about, and then not recalling . Hmmm,,, guess there was a good reason for trying that!

Nevertheless, gjl711 thanks much - now I can sleep tonight,,, knowing that I'm not totally crazy, just partially mostly.

Happens all the time. My thing is MLU. I always forget I have it set and when I go to press the shutter, no pic.

gjl711 wrote in post #11629464
Happens all the time. My thing is MLU. I always forget I have it set and when I go to press the shutter, no pic.

still takes me a while to remember i have moved af start to back button. every time i halfpress the shutter i wonder why the af doesn't move: "it isn't that dark in here, why won't it engage?"...