Video cameras work by focusing an image on one or more CCDs (charged-couple devices), which then convert the resulting electrical signals into an image. The problem is that CCDs are smaller than 35mm film frames, and usually smaller than 16mm film frames, too. Therefore, for a given camera-subject distance and framing, the focal length used by video cameras to produce an image is shorter than for a 35mm camera, so the depth of field is greater. In other words, the background behind your main subject is sharper when you shoot on video.
The reason for which this is undesirable is, once again, perception: having the background out of focus makes the action more compelling and simply looks better. Above all, it draws the viewer a lot more into the world you are creating, because if the background is too sharp it competes with the foreground subject, massively weakening the effect of the shot. (Some people claim that shallow depth of field is only associated with film for historical reasons, but this is highly debatable, as the aesthetic and storytelling benefits of a shallow depth of field are obvious.)
To throw the background out of focus as much as possible, the focal length must be as long as possible (so move back and zoom in) and the aperture must be wide. You should also aim to use cameras with 2/3″ CCDs, as they are larger than 1/3″ CCDs and consequently require a longer focal length for a given camera-subject distance and framing, making the depth of field shallower. Cameras with 2/3″ CCDs also produce images of a higher quality.
Remember that depth of field also depends on the distance between the camera and the subject. The closer the subject is to the camera, the shallower the depth of field. This means that the longest focal length is not always the answer to achieving a shallow depth of field, because it forces you to place the camera further away from the subject. Sometimes an intermediate depth of field results in a shallower depth of field, simply because to keep the framing constant, the camera has to be closer to the subject.
Neutral density filters are vital when you are shooting outdoors and conditions are very bright. Neutral density filters are placed in front of the camera lens in order to reduce the amount of light that goes through, allowing the use of a wide aperture, which results is a shallow depth of field. In this way you can shoot with your camcorder lens at f2.8 even at midday in the middle of the desert. Some camcorders have inbuilt neutral density filters that can be engaged with a switch, but ideally you should have a range of neutral density filters, in one- and two-stop increments, to be used in conjunction with a matte box.
Having a shallow depth of field also enables the use of visual techniques such as rack focusing (dramatically shifting focus from one subject to another in the frame); as a filmmaker, you want every possible visual tool at your disposal, but rack focusing tends to look lame unless you don’t have a very shallow depth of field. Basically you want the subjects to be so far apart in terms of focus that the viewer has no choice but to look at whichever subject is in focus, simply because the other one is so blurred that the eyes naturally shift to the sharp subject. Even high-end movies get this wrong occasionally.
35mm lens adapters: Mini 35 by P+S Technik, Movie Tube, Red Rock, Letus35 and others
In recent years a number of 35mm motion picture lens adapters have appeared on the market. Examples include the Mini 35 adapter by P+S Technik, the Red Rock adapter and the Letus35. Props to the maker of Red Rock, who made an excellent product an order of magnitude cheaper than some other adapters, and without the ground glass trouble suffered by certain models. It is a straightforward fact that these adapters are the only way to achieve the depth of field characteristics of 35mm cinematography with a 1/3″ CCD camcorder. The tips described above will reduce the depth of field, but will not come close to the blurred backgrounds produced by these adapters.
These DV 35mm lens adapters allow the use of 35mm camera lenses with digital video cameras like the Canon XL2. They work by focusing the image on a ground glass and then projecting it on the CCDs. This results in video images that have exactly the same depth of field characteristics as 35mm film. These adapters can work very nicely indeed, but they will of course require a focus puller who is totally on the ball if the camera-subject distance changes even slightly during the take.
Shoot video with a shallow depth of field
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Video cameras work by focusing an image on one or more CCDs (charged-couple devices), which then convert the resulting electrical signals into an image. The problem is that CCDs are smaller than 35mm film frames, and usually smaller than 16mm film frames, too. Therefore, for a given camera-subject distance and framing, the focal length used by video cameras to produce an image is shorter than for a 35mm camera, so the depth of field is greater. In other words, the background behind your main subject is sharper when you shoot on video.
The reason for which this is undesirable is, once again, perception: having the background out of focus makes the action more compelling and simply looks better. Above all, it draws the viewer a lot more into the world you are creating, because if the background is too sharp it competes with the foreground subject, massively weakening the effect of the shot. (Some people claim that shallow depth of field is only associated with film for historical reasons, but this is highly debatable, as the aesthetic and storytelling benefits of a shallow depth of field are obvious.)
To throw the background out of focus as much as possible, the focal length must be as long as possible (so move back and zoom in) and the aperture must be wide. You should also aim to use cameras with 2/3″ CCDs, as they are larger than 1/3″ CCDs and consequently require a longer focal length for a given camera-subject distance and framing, making the depth of field shallower. Cameras with 2/3″ CCDs also produce images of a higher quality.
Remember that depth of field also depends on the distance between the camera and the subject. The closer the subject is to the camera, the shallower the depth of field. This means that the longest focal length is not always the answer to achieving a shallow depth of field, because it forces you to place the camera further away from the subject. Sometimes an intermediate depth of field results in a shallower depth of field, simply because to keep the framing constant, the camera has to be closer to the subject.
Neutral density filters are vital when you are shooting outdoors and conditions are very bright. Neutral density filters are placed in front of the camera lens in order to reduce the amount of light that goes through, allowing the use of a wide aperture, which results is a shallow depth of field. In this way you can shoot with your camcorder lens at f2.8 even at midday in the middle of the desert. Some camcorders have inbuilt neutral density filters that can be engaged with a switch, but ideally you should have a range of neutral density filters, in one- and two-stop increments, to be used in conjunction with a matte box.
Having a shallow depth of field also enables the use of visual techniques such as rack focusing (dramatically shifting focus from one subject to another in the frame); as a filmmaker, you want every possible visual tool at your disposal, but rack focusing tends to look lame unless you don’t have a very shallow depth of field. Basically you want the subjects to be so far apart in terms of focus that the viewer has no choice but to look at whichever subject is in focus, simply because the other one is so blurred that the eyes naturally shift to the sharp subject. Even high-end movies get this wrong occasionally.
35mm lens adapters: Mini 35 by P+S Technik, Movie Tube, Red Rock, Letus35 and others
In recent years a number of 35mm motion picture lens adapters have appeared on the market. Examples include the Mini 35 adapter by P+S Technik, the Red Rock adapter and the Letus35. Props to the maker of Red Rock, who made an excellent product an order of magnitude cheaper than some other adapters, and without the ground glass trouble suffered by certain models. It is a straightforward fact that these adapters are the only way to achieve the depth of field characteristics of 35mm cinematography with a 1/3″ CCD camcorder. The tips described above will reduce the depth of field, but will not come close to the blurred backgrounds produced by these adapters.
These DV 35mm lens adapters allow the use of 35mm camera lenses with digital video cameras like the Canon XL2. They work by focusing the image on a ground glass and then projecting it on the CCDs. This results in video images that have exactly the same depth of field characteristics as 35mm film. These adapters can work very nicely indeed, but they will of course require a focus puller who is totally on the ball if the camera-subject distance changes even slightly during the take.
Cheap camcorders