How to blur a background image to create photorealistic depth of field?

[RealAnise]

Hi all,

I have a number of free background images that were created in 3D programs (and always picking up more.). My separate render file of the figure(s) is then added to each of these, and the two are composited. The problem is that the background files NEVER seem to have depth of field. Everything is in equal focus, which looks weird and unrealistic. Blurring the entire background out and keeping the separate image of the figures in focus on the foreground layer isn't much better. So here's the question.

How can I blur the separate background image with a realistic perspective/depth of field-- the front of the image less blurred and then the blur gradually increasing as it moves towards the back, so that it looks exactly like what you'd see in a photo or on film? Example: A tree right next to the figures would be less blurred, the ground leading back to the door behind them would be more blurred, the mountains in the distance are the most blurred, etc, on a subtle continuum.

Thanks in advance to all the smart people here for their ideas!

[K´mo]

You can use Lens blur for that. You have to make a depth map for that or you can even get that from 3D software. Check Photoshop help for details.

[Dynamic Office]

If we could see the images I'd be able to provide a more in depth solution but here's how I'd tackle it;

Bringing the image into photoshop, separate the foreground and the background using the polygonal lasso tool, making them two separate layers to work from for ease.

On the background, play around with blur tool starting small and gradually increase until the desired effect, I'd also add a very subtle blur to the foreground image just to bring it together.

Again, if I could see the image I'd be able to break it down further and go a bit more in-depth

[Vishu_Aggarwal · Accepted solution]

You can use the combination of Iris Blur and Field Blur under the filters > Blur to create the required effect.

Have look at video tutorials created by adobe to use the Iris Blur and Field Blur -

Photoshop Playbook: Selective Focus - YouTube

Russell Brown: Tips and Techniques for Using Tilt Shift, Iris Blur, and Field Blur in Photoshop CS6 ...

I hope this helps you to achieve the required effect.