Depth of Field

This week will be a very busy very painful week.  I am trying to close out the quarter, I have office days planned but with a ton of tentative meetings possible.  Today did not disappoint it was spent at my desk all freakin day, so the photo of the day would be one of those "around the house" quick ones. 

Fortunately, when I was trying to catch a lizard in the house yesterday(see yesterday's blog) I noticed something that might make for an interesting picture.  Plus when you have a 2.8 long lens like my 70-200 you really can work the Depth of Field idea.  On our wall in the living room we have these really cool round mirrors with a matching round clock, courtesy of Bed Bath and Beyond and those 20% off coupons.  The clock at the top of the picture, I melted on January 4th of this photo blog(http://greggvscamera.blogspot.com/2013/01/salvador-dali-is-turning-over-in-his.html).  You can kind of see the mirrors in the blog on June 25th (http://greggvscamera.blogspot.com/2013/06/freebird.html) . 

Anyway, today I decided to work the depth of field idea by shooting into the Mirror.  Now I have done a little depth of field project before on May 9th with golf balls where the focal point was the back of 4 balls, it was in focus but the front ball was out of focus.  (http://greggvscamera.blogspot.com/2013/05/one-track-mind.html)

So while I think today's photoblog picture is cool, I now ask my photo friends following this blog, how is it that the image of me in the mirror is tack sharp, but the image of the clock above which is exactly the same distance away as the mirror is out of focus?  Maya, at the bottom of the picture, is about a foot closer so the fact that she is blurred makes sense to me, but the clock has me stumped.  This photo is untouched except to crop a tiny bit to center the mirror.