Adjusting The Lens - Swann PRO-780 User Manual

Pro-series
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FOCUS: The right hand dial controls the focus.
Adjusting the focus control is kind of like trying
on a different pair of glasses - it can make sharp
things look blurry and blurry things look sharp. It's
not quite magic, but it's pretty close.
Basically, once you've set the zoom, twist the
focus knob until what you want to see doesn't
look blurry anymore. If you can't turn the knob
any more one way, go back the other.
You can only have so much in focus at once -
photographers refer to the size of the area in
focus as the "depth of field".
The diagram to the right shows a couple of
different focusing options. The shaded areas
represent the depth of field. As you can see, there
is no hard edge, some things are "more" in focus
than others.
Note that this is for illustrative purposes only - there are many factors which contribute to depth of field
which vary from location to location.
A: The lens is at its widest, and focused on an
area relatively close to the camera. The depth of
field is quite large.
B: The lens at its widest with focus set to "infinity".
Anything in the shaded section will be in focus,
and this focus extends to infinity (that is, things
in the far distance will also be in focus). However,
things in the distance might be too small to see
the detail you require.

Adjusting the Lens

23°
81°
The zoom and focus controls are located on the
rear of the camera.
ZOOM: The left hand dial controls the level of
zoom. You can vary the viewing angle between
23° and 81°. This is an approximately 3x optical
zoom, which operates in a similar manner to the
zoom on your digital camera. Basically, zooming
in makes everything appear to be larger, at the
expense of the viewing area.
Check out the diagram to the left for a visual
representation of the zooming process.
The smaller viewing angle (marked 23°) represents
the camera's view when "zoomed in", and the
larger angle (81°) represents the camera's view
when "zoomed out".
You can set the zoom to either of these extremities,
or anywhere in between.
When you change the zoom, you'll also have to
change the focus. Why? Lenses are complicated,
and all the bits are joined together. Changing the
zoom will also change the focus.
A
B
C: The lens at its tightest, focused on an area
close to the camera. As you can see, the more
the lens is zoomed, the smaller the depth of field
becomes.
D: The lens at its tightest with focus further from
the camera. At this distance, the actual depth
of field is much larger, but it doesn't extend to
infinity like it does when the lens is wide.
C
D
3

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