Many people think achieving a shallow depth of field on DV formats (especially Mini DV formats with smaller 1/4 inch CCDs) is virtually impossible. Although it can be difficult, it is not impossible.
Here are some tips for achieving that Hollywood style narrow depth of field effect. First, make sure your subject is placed as far away from the background as possible, this will make throwing the background out of focus much easier. Next, move your camcorder a considerable distance from the subject, this will force you to use the extreme end of your camcorders zoom range. Using a tripod (this is essential when zoomed right in to avoid shaky images, remember, when the image is magnified in this way, every tiny movement is magnified too) zoom right in and compose your shot accordingly.
Next, set your camcorders aperture to it’s widest setting, although there will be a slight drop in image resolution and quality, this is the trade off you have to make to achieve a shallow depth of field. I won’t go into the scientific side of why this works, but this wide aperture will help enormously in achieving a shallow depth of field.
Now, because you have set the aperture manually it will almost certainly affect your exposure (it will probably be overexposed by now), compensate for this by using ND (Neutral Density) filters, either the camcorders built in ones (if it has them) or the glass variety that screw onto the front of the camcorders lens. Company’s like Hoya, Lee, Tiffen and Formatt make good quality glass ones.
If you follow these basic rules you will achieve a very respectable shallow depth of field, even from camcorders with smaller 1/4 chips. This technique should also be applied when carrying out “Pull Focus” shots to make the effect more obvious