Interesting question. I found the Breezebrowser feature description to learn more about this functionality they call Focus Point Overlay
. In short: Pretty cool.
| Focus Point Overlay |
Right click on the image and select "Show Focus Points" to overlay the focus points used when the picture was taken. Alternatively select "Show Focus Points" from the "View" menu. Active focus points are shown in red and inactive ones in black.
Please note: This feature is available with images from Canon EOS cameras only (D30, D60, 10D, 300D, 1D, 1DS and 1D Mark II). The focus points may not be displayed correctly with portrait format JPEG images because it isn't possible to know whether the camera was rotated clockwise or counter clockwise when the shot was taken.
I've been surfing via Google for awhile now, but I'm not seeing a PS equivalent. I'm sure if CS could do this, Adobe would not be shy about promoting it.
If I find anything, I'll sure post it.