[Tok_Tok]

Don't know if something like this is already suggested but this idea just popped into my mind.

A shader for the viewport that is suggesting the depth of field. So just as in Studio 2 colors (red & blue), but here ON the scene objects themselves, red meaning close blur and blue the far blur.
Maybe it is even possible to create a gradient between them..

With this you could finetune the depth of field very quickly and precise.

[Francois_vd_W]

Yes please

[Sebastien Bernard]

Yessss like in Octane they are implemanting this and it is very impressive...

[Tok_Tok]

Not exactly as in Octane. That is realtime rendering, that's btw very impressive!! I dont think they will be implementing GPU rendering so I hope maxwell didnt miss the boat on that one.

What I meant is a shader to preview the depth of field, in the viewport.

[Sebastien Bernard]

I totally agree but it would be so nice to see in the studio wich objects are blured or sharp according
to F-stop... instead of waiting for the render.

[JorisMX]

I would encourage this as well

however I have the feeling w/o any GPU power this will never happen.

Just see how much heavy DOF settings slow down the render...
Sometimes the difference to non DOF and DOF can be hrs in higher res...

Perhaps if you remain in lowres preview and accept some more quality drops then there could be away

[gadzooks]

This would be a nice addition. You get my vote

[rusteberg]

ability to display depth pass in FIRE would be helpful....