i wonder, is there any kind of software able to spot where is the focus in a given picture and to eventually assess if the area is big enough ?

i think it could be doable mapping the image and then checking for areas with higher color/contrast intensity but i have never ever heard of any tool doing something like this.

Nikon Capture only works for nikon cameras and it's using EXIF data to spot the focus, i need something totally different fromt this, ideally i could check a batch of hundreds of pics and the software will automatically sort out of the bad apples with bad or poor focus.

by the way, similar concept for automated softwares who can spot minimal camera shakes !

BTW, I'm not sure if Nikon Capture reports the actual spots in focus or just the sensor spots that were used for focusing.

i'm sure the camera has no way to be 100% sure if the image has been shot in perfect focus or horribly shaken.
that's where a focus analyzer would come handy but i think it's not yet been invented hahaha ...

The RAW editor/converter Capture One has the option "show focus mask" that highlights all areas that are "sharp" with 50% green.

See here for more details:

<a href="http://youtu.be/ypX8j8TtGjw?t=1m58s" target="_blank" class="aeva_link bbc_link new_win">http://youtu.be/ypX8j8TtGjw?t=1m58s</a>

You could ask Shutterstock about this.  But they won't answer.

I know only this (it works with Lightroom 5):
http://lightroomfocuspointsplugin.com/

thanks a lot ! downloaded and will try tomorrow !

yes, it works only with canon/nikon picking up EXIF focus data, just as Nikon Capture does.

I use capture one's green mask to check focus in studio shoots. It works pretty well.

confirm !
it works fine and it can also be fine tuned, Capture One rocks !