I found a link to some PDA apps that have two utils I find handy for calculating/understanding DOF and Exposure. I tend to find these elements somewhat confusing so having loaded them on my pda and played with various settings, they give you a little more understanding.
DOF1 and Expose1 are the names:
http://www.dl-c.com/Temp/
Click on the downloads button at the top. Then scroll to bottom of screen, click on pocket PC freeware link.
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