Re: Simulating Depth of Field using Photoshop Lens
You can play around with the filter settings (including the specular highlights) to try to mimic the non-ideal bokah of a lens. Another trick is to reduce contrast slightly in the blurry areas. This tutorial was quite simple and extreme so the effect would be obviously visible. In practice, there is no lens with a large enough aperture to create the effect shown in the tutorial at the perspective shown, so this particular example will never look "realistic"--or at least it'll look like a photo of a toy bench.
I mainly wrote the tutorial to provide an alternative to the much less-realistic-looking method of masking a gaussian blurred layer.