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Things to consider when selecting a security camera
When
considering the selection of a security camera there are a few things
to consider such as lighting conditions, distance to object,
environment (indoor or outdoor) and distance from camera location to
power source and DVR (digital video recorder). Unlike other websites
which just sell products, we're here to help you in your selection. If
at anytime, you would like assistance please free free to contact us at
562.923.2323 or drop us an email at info@securitysystemsdirect.biz Click Here to Email Us
Camera Features & Glossary
The
follow are camera features and terms. Please note, many terms refer to
our professional grade specialty cameras. These cameras are most often
used for commercial applications.
AUTO FLIP: for PTZ Cameras: in case the tilt angle is at the top or the tilt orbit (at 90°), the zoom module contnues to move in the opposite tilt direction (180°) to keep tracking target. As soon as the zoom module passes through the top of the tilt direction (90°), images should be reversed automatically.
AUTOMATIC GAIN CONTROL (AGC):
a circuit that automatically adjusts the incoming signal and properly
adjusts levels for display and recording. Helps improve performance in
low light conditions
AUTOMATIC IRIS LENS: a lens that automatically adjusts the amount of light reaching the images.
AUTO TRACKING WHITE BALANCE (ATW):
color temperature is directly related to the environment and its
influence on the color image. ATW automatically adjusts the white
balance in response to varying light conditions.
BACK LIGHT COMPENSATION (BLC):
the
ability of the camera to balance the lighting in a scene with an
extremely bright background such as sunlight. It helps to capture the
finest light contrast and receive a clearer image on the image in front
of the back lit area.
BNC CONNECTOR: a type of wire connection device that is often used with CCTV products, for connection between two wires.
C MOUNT: a camera lens mount of the 16 mm format, 1 inch in diameter with 32 threads per inch.
CCD (CHARGED COUPLED DEVICE):
a semiconductor imaging device which changes light energy into an
electrical signal to produce an image. The CCD imager scans the image from the lens after a series of transfers through the mechanical components of a camera, adjusts the image to view into your monitor. SecuritySystemsDirect.biz uses Sony's high
sensitivity CCD (Super HAD or Super HAD II), Vertical Double Scan and additional Sony CCD's.
CMOS (COMPLEMENTARY METAL-OXIDE SEMICONDUCTOR):
a digital image sensor composed of several pixels over standard CCD's. We use PIXIM® chipset or other high grade CMOS sensors found in professional grade cameras.
COAXIAL CABLE: a particular type of cable capable of passing
a wide range of frequencies with very low signal loss. Such a cable in
its simplest form consists of a hollow metallic shield with a single
wire accurately placed along the center of the shield and isolated from
the shield.
COVERT: a device with is hidden and unseen to the naked eye.
DAY/NIGHT: Day/Night
Cameras are color cameras which automatically switch to black &
white at night or in low light conditions to allow for visible images.
When the lighting conditions change back for more lighting or daylight, the camera
will auto switch back to color.
DEPTH OF FIELD: the in-focus range of a lens or optical
system. It is measured from the distance behind an object to the
distance in front of the object when the viewing lens shows the object
to be in focus.
DIGITAL NOISE REDUCTION (DNR):
digital technology that supplies clearer images over standard analog by reducing the image noise of pictures. What is 3D-DNR?
A
newly developed 3D filtering that enhances standard Digital Noise
Reduction at extremely low
light levels. The results create decreased signal-to-noise ratio which
greatly improves low light visibility when using a sens-up
function. Found in professional grade cameras.
DIGIAL SIGNAL PROCESSING (DSP):
A new processing technology used in a variety of digital applications
from cell phones, digital cameras and audio players to security
equipment. For security cameras, DSP converts visual images and sound
waves into digital signals. The advantage of DSP results in clear,
high quality enhanced digital signals. This
allows for higher definition images and signals to be sent over greater distances without data loss. DSP helps in automatic compensation for backlight interference, color balance variations and corrections related to aging electrical components or lighting. Found in professional grade cameras.
EXTREMELY LOW LIGHT/SENS-UP CAMERAS: This technology is the newest development to the security industry to
eliminate the need for IR's at night. The Extremely Low Light Cameras will show as having a 'sens-up' feature. This feature indicates the camera is
sensitive to light at 2x, 4x, 8x, 32x, 64x & 128x Sens-Up Speed.
When enabled, the 'sens-up' allows the camera to draw surrounding light
into the imager and use it's digital slow shutter speed to offset the
standard frame rate to capture a color image in the dark. Lux level is
often shown as 0.0001 or lower.
These camera have the ability to remain color the longest however, the
greater the sens-up feature is set, the more the frame rate drops.
What does this really mean.....the greater the sens-up, the less frame
rate to the camera, the harder it is to capture moving objects
clearly. Knowledge of the CCTV industry is highly recommended when
using these cameras. There are adjustments which need to be made
in order to bring out the 'sens-up' features to allow for usable
captured images.
EX-VIEW: Ex-View Cameras are color cameras which have an ultra low lux level
allowing for color images in lower lighting environments. When the lux
level has been reached, the images will no longer be viewable. Good
for areas such as parking lots where constant low light at night is
present.
F/STOP: refers to the
speed or ability of a lens to pass light. It is calculated by dividing
the focal length of the lens by its diameter.
FIELD OF VIEW: the maximum angle of view that can be seen through a lens or optical instrument.
FOCAL LENGTH: related to a lens, the distance from the focal point to the principal point of the lens.
GAIN: an increase in voltage or power, usually expressed in dB.
HIGH LIGHT COMPENSATION (HLC): A feature in specialty professional grade cameras such as license plate capture cameras. User can set a special viewing area as the "target object" under strong spots of lighting. The HLC will reverse bright points in the picture to black and improves the ability to display shades of grey elsewhere in the picture. By doing so, it will enable the target area to become visible to view numbers such as license plates. Also referred to as HLBLC or Eclipse.
 INTERLINE TRANSFER CCD: while a full CCD changes light energy into an electrical signal
to capture images, an Interline Transfer CCD, controls the start/stop
of when it measures light (electronic shutter) and than shifts the
images out as a final image. The advantage is that it be controlled by
software and doesn't require a mechanical shutter to produce the image as standard CCD's do. Because Interline Transfer CCD's do not need an external shutter, cameras based on this technology are typically less
costly than those using full frame CCD's.
IRIS: an adjustable aperture built into a camera lens to
permit control of the amount of light passing through the lens.
LENS SPEED: refers to the ability of a lens to transmit
light, represented as the ratio of the focal length to the diameter of
the lens. A fast lens would be rated f/8. The larger the number, the
slower the lens.
LUX:
light unit for measuring illumination; one lux equals one lumen per
square meter. A term used in the security industry as a means of
measuring a camera's sensitivity to light and ability to capture
images in a given light setting. The lower the LUX, the greater the ability to capture images in
low light areas.
For
example: a camera that sees at 1.0 Lux has the ability to see an image
during the day to early evening hours or just before dusk; after this
the camera may no longer be able to capture or see images. An IR/Night
Vision Camera with a Lux of 0 will automatically turn on it's IR's to
illuminate the area when the LUX drops to below 0 at which time the
color image will change to black & white. A camera at or below
0.005 LUX has the ability to see an image in the dark at night without
any light or IR's. A 0.005 Lux rated camera may 'see' better than the
human eye at night.
ON SCREEN DISPLAY (OSD): an onscreen display menu that can be accessed from the camera to access multiple functions & features built-in to the camera. Users can then setup various functions like sens-up adjustment, color saturation, WDR, etc.
PAN AND TILT: a device upon which a camera can be mounted
that allows movement in both the left to right (pan) and in the vertical
plane (tilt up and down).
PAN-TILT-ZOOM (PTZ) CAMERAS: cameras that
can pan left or right, tilt up and down and zoom into and out of a
viewing area. These functions can be accessed and controlled using
either a PTZ keyboard or an on-screen PTZ controller through a DVR.
Professional CCTV knowledge is highly recommended.
PRIVACY MASK/MASKING: for
protecting personal activity, the user can set a zone to be free from
recording and viewing images. It blocks out an area that is user
defined.
PROGRESSIVE SCAN: the progressive scan format outputs data
from the camera in sequential order as it scans. The
scan format produces a full frame of video in a continuous stream,
rather than half the image per output sequence in traditional cameras.
REAR TIME: receiving a video signal that is at the same time in which that signal is actually occurring.
REGULATED POWER SUPPLY: a power supply that provides a constant output regardless of voltage variations.
RESOLUTION: in an electronic image, a measure of the
reproduction of fine detail, typically expressed in terms of number of
vertical and horizontal lines. In a digital image, the total number of pixels in the horizontal and
vertical directions. The higher the resolution, the clearer the image.
VARIFOCAL LENS: contains several movable elements to permit manual adjustment of the
effective focal length. This type of lens allows you to adjust the size of
your field of view.
WIDE DYNAMIC RANGE (WDR): very specialized feature with limited and specific applications. This
technology allows for a clear image in situations where there is varied
lighting demands or a large dynamic range of lighting. These
cameras are typically used when directed toward a large window or
entrance door where large amounts of light (or sunlight) will have an
effect on the image. For cameras not using WDR technology,
images may appear washed out or extremely dark due to the high brightness. How
does WDR work? Simply stated it uses two shutter speeds (high &
normal) to alternate the images and than combines the images into one
frame for a clear, detailed picture - just as a filter offsets bright
& dark images to produce one clear image. What is D-WDR? Digital
Wide Dynamic Range is a new powerful and ultra advanced technology that
captures cleaner and superior high resolution pictures over standard WDR using the newest in digital technology. WDR cameras are typically used for
restaurants, retail stores, markets and offices. Below is an example of
a three images: without WDR, using standard BLC (back light compensation) and
WDR Technology.  ZOOM LENS: an optical system of continuously variable focal length, the focal plane remaining in a fixed position. |
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