I followed a link from a popular newsgroup to this company’s FCP uninstaller.  But this DOF calculator caught my eye instead.

 

Those of us who are shooters are often trying to shoot and light interviews were the background is out of focus (to draw more viewer attention to the interviewee). With this handy online calculator you can now know precisely where that depth of field lies.

 

There is also a version for mobile phone users.

 

www.digitalrebellion.com/dof_calc.htm