The Gimp has a focal blur plugin that uses a greyscale image map to describe focal levels (white: fully in focus, black: fully out of focus and levels of grey somewhere in between). Since TG2 is already aware of the distance of specific objects in the scene, it seems that it would be ideal for TG2 to produce a greyscale image that conforms to such a focal blur plugin as long as a focal point is described. I believe other focal blur plugins (i.e. Photoshop) can work with a similar greyscale imagemap concept to describe focal blur. So, while I would love to see focal blur actually in a TG2 render, allowing creation of a greyscale blur map would suffice as a suitable alternative to creation of focal blur directly in the render. To apply the blur, it would be a reasonably simple step to open the gimp, import the image and the blur map and apply the focal blur. The severity of the blur (F-stop) can be controlled directly in the Gimp.. so there's really no need to try to determine different F-stop levels within TG2 (at least initially).
Doing such a map by hand is possible (and I've done it). However, because of the randomness of doing it by hand, it's not suitable for animation. Offering such a blur map render in TG2 would allow for using focal blur for animations without having to build a focal blur system directly into TG2. However, focal blur would require two renders (one for the image and one for the blur map).
Thanks.
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Brian
