is it necessary to calculate hyperfocal distance with dvx?

[IndyUser500]

Hi,

I was reading up on hyperfocal distance and using it to get in focus shots from 1/2 that distance to infinity.

What I was reading seemed to appy to still cameras. Would this also apply to the DVX/could anyone describe their experience using hyperfocal distance with it?

this is what I was reading http://www.dofmaster.com/hyperfocal.html

 

[andy_starbuck]

The information on hyperfocal distance is technically accurate and applies to all lenses and photography. However, the circumstances are different for most video cameras than for most still cameras.

Most still cameras use 35mm sized film or sensors and a 35mm lens. This combination leads to extremely shallow depth of field. With this configuration it is easy to get something in sharp focus with a blurred background. But it is relatively hard to get something nearby in focus, and also have the background in focus out to infinity.

For example, imagine a tree about six feet in front of the camera, and beyond that the grand canyon. Getting both the tree and the grand canyon in focus with a 35mm camera would be a trick. Many still photographers would calculate the hyperfocal distance to know how to set the camera's focus and aperture in order to get such a deep focus shot, just as the author does in the article.

With video cameras we are in somewhat the opposite position. Most video cameras (including the DVX) have a small sensor (1/3rd inch) and a large lens which naturally provide deep focus when compared to a 35mm still camera. So getting the deep focus shot of the tree and the grand canyon wouldn't be a problem. However, shallow focus ... which the 35mm still camera excels at ... is more difficult to achieve with the video camera.

For example, if you had a tree about 6 feet in front of the camera, and a fence 20 feet behind the tree, the challenge would be to get the tree in focus but the fence blurred out of focus. With a 35mm still camera this is no problem. But with a video camera this look is harder to achieve.

Because indie filmmakers often want the look of traditional film movies, which are shot with 35mm film and lenses, we often want that shallow depth of focus look which is difficult to achieve with video.

What is often more important in using video cameras is to calculate the region of acceptable focus, the "Zone of Focus"-- the distance in front of and behind the focal plane that is acceptably "sharp" -- and where objects in the scene will start to appear out of focus. We don't want the back of that zone at infinity. We want it, in our example, in front of the fence that is 26 feet from the camera.

In general, a wider iris gives you a shallow zone of focus. But of course, this also changes the exposure, allowing more light in to the sensors. Calculating the exact region of focus is a bit complicated mathematically, and nothing I usually want to do during a shoot. So a lot of videographers rely on rule of thumb or just on what we see through the camera to guide our settings.
Generally, you open the iris as much as possible to get shallow focus, and then adjust other settings to get the exposure back.


Here is some more information about Depth of Field and Depth of Focus:
http://www.btinternet.com/~focal.plane/tutorials/lenses/tutor2p1.htm
and
http://en.wikipedia.org/wiki/Depth_of_focus



Hope that helps.

Andy