Originally posted by ManhattanProject Yea... I always use 100 outside from dawn to dusk.
I'm the exact same way, unless it gets real overcast and I have to go to 200. But people have posted here that it's not a true 100. And remember that you have to have Expanded Sensitivity On and Highlight Correction Off to have 100 available.
BTW:
Does the OP realize that on the K-x (and I assume other Pentax DSLRs), your range of available ISOs is linked to your preferences for Ev (exposure compensation)? In other words, if you have your Ev settings at full stops, you will only be able to select ISO 100, 200, 400, etc. But if you have it set to 1/3rd of a stop, you'll have available like 100, 135, 175, etc.