Two Minute Tip: Fake Tilt Shift Lens Effect

[timar03]

for a more accurate and realistic effect use "lens blur" filter with an alpha channel as depth map.

[NicolesyPhotography]

I've done both ways, and IMO the gradient is quicker, especially for beginners. If you make your own preset gradient (transparent-black-transparent­) then it can work really well and fast though, too. :)

[pawelryczek]

using gradient instead of just a rectangle works way better. you get a smooth transition between the sharp and blured areas.

[frankytap]

@pawelryczek gradient blur ?