Page 57 - NyghtVision Boot Camp One Fill Edition
P. 57
has a greater depth of field than an F-stop of 2.8. given situation is? There are really only two ways:
If you think about it for a moment, there is a logic read the manufacturer’s specs on line, and expe-
to this. The longer the camera looks at the world, rience.
the more it sees. At an F-stop of 8, the camera will
look at the world longer than it would at an F-stop There is a third, more practical rule: Depth of field
of 2.8 so its sense of space is greater. is always 1/3 in front of the focal point (where one
has focused) and 2/3 behind that point.
Keep in mind, however, that depth of field varies
from lens to lens. A Canon 85 prime (not a zoom However, if you photograph an object dead on as
lens) at F 16 has a depth of field that matches that we like to say (directly in front of an object) depth
in the Canon 70-200 L series lens at 2.8. The de- of field won’t matter since the image will look flat
sign of the lens has that much of an impact on to the camera.
depth of field. So, Always take an angle. There is another way we
can enhance the camera’s sense of space, as we
What exactly is depth of field. According to the shall see later in this chapter, but for the moment
classical definition, depth of field is that area of lets talk about the circle of confusion.
an 8x10 that is sharp and clear when one is stan-
ding one foot in front of that image.
Inbetween depth of field and that area of an ima-
That doesn’t make much sense, nor is it terribly ge that is totally out of focus is the circle of con-
practical since we can’t stop in the middle of a fusion. We call this area of an image “soft”. It is
shoot and apply that rule to the situation at hand. sharp enough to engage the eye but not sharp
It just doesn’t work. enough to be in focus. Depending upon how you
compose an image, th circle of confusion can be
So, how do you know what the depth of field in a equal to or even greater than depth of field.
Seeing the World Again. For the First Time. 57
