@stonebat

But with a longer focal length, you have to be further away to keep the subject the same size (keeping the subject the same size is important in this case). That longer camera to subject distance will give you also a deeper DoF.

I'm not sure if that comment from my first post is 100% true, but I have read it several times lately on very good video/photography pages.

Thanks for the comments everyone.

By the way, all the dimensions are in meters. Both the DOF ranges (vertical) and distance from the camera (horizontal).

@balazer, If video recording is using the same portion of the image sensor as still image capture. I don't see how the DOF would be different. As far as I know, the circle of confusion is not resolution dependent. I get the idea of perceptual differences of DOF at different print/screen sizes and resolutions. Can you explain what you mean?

@Psyco, not sure about your first comment. But in terms of shallow DOF, thats the conclusion I made. If you want shallow DOF, get your subject as close to the cam as possible and use a fast lens:)

@Kihlian, Yes this is a great site. I mentioned it in my blog post, as this is what I based all my calculations on. For sure, there are times when you need a deep DOF. I was more interested in researching shallow DOF at maximum aperture, so this research is slanted in this direction. Great to hear these calculations hold up in reality.

Isn't the DoF the same for every focal length, as long as you keep the subject in focus the same size and use the same F-stop?

So, if you want shallow DoF you need a faster lens or let your subject appear bigger.

I take it your circle of confusion size is selected to match the resolution of the GH2 in stills mode. Video resolutions will have greater depth of field.

Depth of field comparisons for different lenses are more intuitive when made in terms of the aperture diameter instead of the f-number.