Getting shallow DOF on digital camcorders
Alright, so you’re trying to film a scene that has some depth to it, like a fairly distant background with some stuff in the foreground. However, you really don’t want that background to be shown in the scene as it’s too busy and doesn’t help portray your message. So you try just to focus your digital camcorder on the foreground hoping the background will be blurred out. But, to your horror, you find everything is still in focus even if you zoom in on just the foreground.
This effect is really all to common in lower end digital camcorders (actually even low end prosumer models have issues with this). The problem is caused by the physical size, not pixels, of the CCD chip inside the camcorder. The larger the CCD, the greater your ability to shorten the depth of field which will blur out anything not in focus. This is why in movies you see this great shallow depth of field because either they’re using really expensive, and I mean expensive, digital camcorders or 35mm movie cameras. The 35mm movie cameras obviously use 35mm film which has a much larger surface area that the picture is captured on compared to cheaper digital camcorders’ CCD.
However, there is a fix for this, and it doesn’t even involve ripping apart your $2000 camcorder to replace the CCD. You can build an adapter that allows you to take lenses from 35mm SLR still cameras and attach it to your camcorder. There’s a couple of different styles documented around the internet, but they all are based on this basic principle. You take the 35mm lens, set it the proper distance from a ground glass, and then focus your camcorder onto the picture displayed on the ground glass.
The style I’ll be building is documented at Daniel’s 35mm Adapter site. I’m going for the static version, as my Canon GL2 camcorder isn’t HD. So far, I got an old Canon FD lens, an achromatic lens to allow my camcorder to focus on the ground glass, a Nikon ground glass, and some parts from Daniel’s site to hold it all together. Keep an eye out for further updates on this project as I get the rest of the parts.
Posted by g1powermac under Filming | Comments Off