Light meter Calculator

[Kahn10]

I wrote a calcutator to give me quick numbers for lux or FC values. I was hoping to get opinions on accuracy or improvements. The program his here:

http://www.allthingscomp.com/lightcalc.htm

The layout is cramped because I wrote it to fit on my PDAs screen. in landscape and full screen it fits perfectly. Also because of space constraints I put the table button below the light value area, I know it's not the most intuitive spot but it seems to work well. I also added number buttons to the bottom as the keyboard on my PDA is cumbersome. Those buttons will enter numbers into the light meter reading area.

All constructive criticism is appreciated.