What's depth of field and what's depth of focus

<P>Hi Guys</P>
<P>Do you know the definition of the "<b>depth of focus</b>" and "<b>depth of field</b>" ?</P>
<P>And what's the difference between them ?</P>
<P>Thanks for your help.</P>

No difference. Here is an artical that can resolve your problem clearly!

http://www.microscopyu.com/articles/formulas/formulasfielddepth.html

景深和焦深，好好看看书

:) 基本概念应该自己看书。