Chapter 5 Lenses - StarDot Technologies NetCam SC User Manual

Chapter 5
The Focus Ring
In most packages, NetCam SC ships with a pre-focused lens. Most
lenses available for NetCam SC also have a focus ring which allows you
to focus the lens for a closer subject. The focus ring may be marked in
meters:
0.2m -- 0.3 -- 0.4 -- 0.5 -- 1.0 -- ∞
The ∞ stands for infinity. Turning the focus ring to 0.5 meters will yield
a focus of half a meter. Turning it back to the infinity symbol will yield an
infinite focus again.
Some lenses will not have the numerical markings -- they may be
marked only with "near" and "far". The "far" setting is infinity and the
"near" setting is the closest the lens will be able to focus, which varies
from lens to lens.
The Iris Ring
Many lenses available for NetCam SC come with a manually adjustable
iris ring. In indoor lighting situations, you will usually want the iris open
to its fullest position. In outdoor lighting, you may want to set the iris set
to a smaller size. The iris ring is usually marked in ƒ-stops:
1.3 -- 4 -- 8 -- 16 -- C
The C stands for closed. In this example, the 16 setting is the smallest
marked iris opening and 1.3 is the largest. You can set the iris to settings in
between the marked numbers (setting it between 16 and C would result in
a setting closer to ƒ22, which is even smaller than ƒ16).
Some lenses do not contain numerical iris markings, but will be marked
with "open" and "close". You will need to look in the lens to see the size
of the iris when placing NetCam SC outdoors, or you can evaluate the live
video when adjusting the iris.
Changing Lenses
Changing lenses sometimes requires a back focus adjustment of the
new lens. Back focus is the adjustment of the chrome ring that the lens is
screwed into. Follow these steps when replacing a lens.
1.
2.
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Lenses
Unscrew the original lens from the chrome back ring and com-
pletely remove it.
Determine if your lens is C-Mount or CS-Mount.
The only difference between a C-Mount lens and CS-Mount lens
is the C-Mount lens requires a 5mm spacer between the lens and
NetCam SC