DVR Comparison Chart - Compare our Latest Digital Video Recorders (PDF)
If you, like many of our customers, know you need a camera but don't know exactly what you need, think carefully about your application. We've included some helpful information below on the types of cameras and how they may be put to use. If you are a business owner or operator, we have some special considerations for you:
Covert vs. Non Covert Cameras
- Would I rather catch a thief or deter potential thieves from stealing?
- Do I wish to deter external thefts and/ or robberies?
- I may have a way to hide the camera, but can I hide the DVR and monitor from the employees as well?
If your primary goal is to deter potential thieves, you do not need a covert camera. For this application, we recommend a small and unobtrusive camera system. As your goal is to remind employees and potential thieves that someone is watching, the camera may be placed in a location that is clearly visible to all. In addition, you do not need to find a hidden place to set up the monitor and DVR. If this is your application, scroll down the page and check out the types of unobtrusive cameras available, or give us a call and let our trained professionals help you to find the right product to best suit your needs.
- If you wish to covertly monitor your employees or customers, we can certainly offer a variety of products to suit your needs. However, as we believe in putting our customers first, we want to point out to you the following considerations:
- You will need to ensure that not only is your camera hidden, but that the DVR and/or monitor are hidden as well. It only takes one employee to spread the word that a camera is in use and where it is located.
- Do you really want to fire and go through the expense of retraining personnel, or do you want to deter wayward behavior from happening in the first place?
- Perhaps you need a combination of covert and unobtrusive cameras.
Should I use Color or Black & White (B&W) Cameras?
This is a simple question. Not only do B&W Cameras typically offer a higher resolution picture while having tremendously better low light capabilities over color cameras, but you can buy them for a fraction of the cost of a Color Camera. Actually, unless noted otherwise, all of our B&W cameras are Infrared Sensitive, and may be used where even the lowest amounts of light may be present. Color Cameras typically demand a greater amount of light to be present for the imaging device to capture a clean, sharp image. Even with more expensive models, Color Cameras tend to "wash out" the color when used in a low light environment. We recommend that you save yourself money by purchasing B&W cameras unless your application dictates the need to see color. This is especially true if you need the camera to see in low light environments. However, we highly recommend that you use a minimum of one Color Camera to cover the public entrance to your site. In the even of a robbery or theft, it is especially helpful in the arrest and later prosecution of the individual to have a full color description of the perpetrator's clothing.
Wireless or Wired Cameras?
At Rugged Marine, we offer wired and wireless cameras, as well as wireless transmitters that you can use with any of our cameras to make it wireless. Wireless cameras and transmitters are perfect for hard to reach installations, or when a road or other type of structure separates the camera from the "monitoring station" where you have your DVR and monitor set up. Being that they are easy to install, they are also great to use if you are "technologically impaired" or are intimidated by the idea of running cable through your structure. However, as with any electrical device that uses radio waves to transmit a signal, their is the possibility of external interference that may make it impractical to use a wireless system. Although our 2.4 GHz cameras & transmitters are mostly immune to common interference, they may not produce a desirable picture under certain (and rare) conditions.
If you're looking for the easiest and simplest way to install a surveillance system and don't mind paying a little extra for the added convenience, go with a wireless camera. However, if you're not installing a in a difficult environment and you don't mind running a little cable, save yourself some money and go with a wired camera.
Remote Access Information you need to know, before you buy your high speed Ethernet connection.
The internet has been wonderful for some time on researching surveillance equipment, finding an installer in your area, and locating a manufacturer to purchase your equipment from.
With in the last several years, the features offered by most stand alone DVR makers, has been exponentially advantageous.
As long as you have a high speed ethernet connection at the site of your DVR you can look at live images as they happen, access all of your archives saved on your hard drives, and manipulate the settings of your DVR like you were sitting in front of it.
Some you can access through a regular web browser, some through CMS (Central Monitoring Software) and you can access multiple locations at the same time - as many as 65 live camera views on one screen, and some even have live access through your PDA and can send you emails when an alarm is tripped.
Picture yourself on vacation with your family. You've been looking forward to some time off for months and you are sitting in your hotel room relaxing and you get a frantic call from your new manager and you had a break in last night. Take a deep breath, get your laptop out, connect to the internet, launch your CMS software and pull up the data from last night. You can see all of your camera views, find the info you need, and make a back up right from your hotel room. You don't have to leave your vacation early to make sure you get the footage off before it is recorded over.
Your PDA goes off at your 'other job' saying an alarm was tripped at the wash. Pull up your cameras on your PDA so you can see your brother already resetting the auto bay that tripped a breaker. He got the message first!
These features can save you time and money. Find a manufacturer that offers the type of access that you need or just find one that offers them all!
When you are trying to determine what Internet Service Provider you should go with to run your remote connection for your surveillance system - several things make a difference.
Download vs. Upload - You will be interested in the upload speed at the site of the DVR, and the download speed at the remote location you are wanting to see the cameras at. Which ever side is lower is your limiting factor. Some providers will say you are getting 512 service which is great, but then you find out that's only download speed, and you are really getting less the 356 upload.
Make sure you ask about both.
Static vs. Dynamic - Static IPs are always going to be less hassle, and more reliable when it comes to your DVR. A lot of DVR manufacturers will have the ability to work with Dynamic IPs, and most do not charge for it. You effectively name your DVR and then access it by the name, which the registration server then keeps track of your IP address when it changes.
Static is normally a few dollars more a month, and well worth it.
Unlimited Tech Support from the company you purchase your camera equipment from, can be worth it's weight in gold when it comes to setting up your DVR and routers for remote access. I have heard it time and time again, customers will call their ISP to open ports to let their video through and the person on the other end of the phone doesn't even know what port forwarding is. This is not a good sign.
So before you buy your DVR, make sure and ask if the tech support staff is equipped to help with the remote setup as well as the camera installation. You'll be glad you did!
1) Mount cameras in location desired. (Mounting screws are included with most cameras, but make sure they are the correct type and length of screw required for the substrate you are mounting the camera to.)
2) Run all of your video cabling back to the DVR and power wire to your transformers or central power supply. If you have PTZ cameras, you will also need to run your data wire. For premade cabling make sure and pull the wires the correct way. The power end of the wires will only connect one way to the camera. Label your cabling on the DVR end and the camera end, so when you terminate your cables what voltage you need and where the wires are running to.
3) Terminate all cables (If premade cabling was purchased your terminations have already been made for you.)
- Video cabling – RG59, RG6 coax, or cat5e data wire with the use of baluns (termination instructions for RG59 coax are included with your toolkit if purchased).
- Power Wires – strip ~1/2” on each end of each wire.
- Data Wires (for PTZs only) - strip ~1/2” on each end of each wire.
4) Never cut molded power connectors off of the camera leads or cabling. Adapter leads have been provided if they are needed.
5) For each of your cameras - connect the video wire at the camera end, and into the video inputs at your DVR. (RS485 Data connections for PTZ cameras as well)
6) For each of your cameras - connect the power wiring at the camera end (male/female connectors for premade cables, and using wire nuts or dolphin splices for any bare wire connections.) MAKE SURE ALLWIRING IS CONNECTED WITH THE CORRECT POLARITY. For low voltage camera wires the POSITIVE WIRES ARE ALWAYS RED! Wrap all exposed connections with black electrical tape or heat shrink to prevent any ground looping or corrosion.
7) Follow the instructions inside your central power supply box for connecting the provided cable for 110V power, and connecting the power cables for each camera. (Knockouts are provided.)
- You can use the supplied electrical cord or you can wire the central power supply box direct from a junction box.
- When wiring the power - keep all black wires together for each transformer to one leg of the power cord (or hot wire from the junction box power), and all the white wires together for each transformer to the other leg of the power cord (or common wire from the junction box power.)
- Red or positive wires should terminate to the numbered or positive terminal.
- Black wire is always negative.
- Camera damage due to incorrect voltage and reverse polarity are not covered under warranty.
8) Double check your terminations and power connections before powering up your power supply and DVR.
9) Adjust your camera position and focus (Varifocal only).
All high voltage electrical connections must be made by a licensed electrician.
(installation may vary depending on exact equipment purchased)
You have unlimited technical support with the purchase of your equipment, so please call with any questions you may have and our staff will walk you right through the installation.
If you have a business and would like to watch your employees but don't know how - we're here to help! We've included some helpful information below in the form of an informal tutorial:
Whether you are considering covert or non-covert, or wired, or wireless, all surveillance systems are similar in nature. They all involve a camera, a way to get the video signal to the monitoring station (where you watch the cameras), the means to view the camera, and often, a way to record the video taken from the camera. Which camera and what equipment to use all depends on your particular application, the venue, your budget, and even your taste.
To see what type of camera is best for you, please see tab on this page "How to Select the Right Cameras for your location." It will compare wired to wireless cameras, Black & White cameras to Color, and Covert Cameras to Non-Covert Cameras. To gain a better understanding of how the entire system works, continue on below.
Wired & Wireless Cameras
Depending on your particular application and the type of structure you're working with, you must first consider what type of camera you would like to use. In short, the options are wired or wireless. While wired cameras have always been the traditional choice of business owners and operators, wireless cameras provide a certain level of versatility and convenience that no wired camera can offer. However, with wireless cameras, you must consider the distance the video signal must travel to reach the wireless receiver, and what type of obstructions it will encounter (walls, floors, machinery, etc.). When choosing a camera system, pay special attention to the maximum range of the unit. Also, wireless cameras may not work well in malls or other places where other businesses may be using similar cameras for their surveillance systems. Too many cameras in one place may cause interference.
When using a wired camera, you must run a video cable to your monitoring/ recording station. If you're not familiar with cabling and what to use, we recommend calling our engineers. Just tell us how far you wish to run the video cable and they will be able to recommend the proper cabling to you. Not only can they sell it to you in bulk, but they will also make sure you have the necessary attachments to hook it up to your camera. Common attachments include adapters that will allow you to attach a BNC cable to the RCA connector on your camera. Adapters and cable ends typically cost just a couple of bucks.
When your surveillance system involves the use of multiple cameras, you must also decide if you are going to use either a switcher, quad or a DVR with these built-in already (usually the most cost-effective, and suitable up to 16 or more cameras).
Switchers typically run for less than $100, and will cycle between all your cameras. You may either manually select a camera to watch by simply flipping a switch, or allow the switcher to automatically cycle through your cameras. Some switchers, typically referred to as "Advanced" models, may also include alarm hook-ups that will automatically pull up a certain camera when an alarm goes off.
Quads are more expensive than switchers. Typically starting at about $250.00, quads, unlike switchers, will allow you to simultaneously record & monitor 4 cameras at a time. It does this by splitting your screen into 4 sections. Similar to switchers, you may manually select a particular camera and pull it up to a full screen view. However, only live images may be brought up to full screen view. Although some quad manufacturers have included digital technology that can bring a prerecorded camera into full screen view, we've found that the image is highly pixalized and does not meet our standards.
BE AWARE THAT OUR DVR's COMBINE ALL THESE COMPONENTS TOGETHER IN ONE SYSTEM - At an affordable price!
TVs & Monitors
Standard Televisions are similar to video monitors, except that TVs also have a built in tuner and typically offer a lower picture resolution to that of a dedicated monitor. In many cases, you can purchase a regular VGA monitor for around the same amount of money and get a better picture.
In short, Remote Video Monitoring allows you to watch your cameras remotely, and in real time, from another location. This may be done either over the internet, your office's intranet, or by "calling into" the cameras over standard phone lines using your computer's modem. All this may be done very simply, and at a very surprisingly low price. Our Digital Video Recorders are perfect for watching your employees & business(es) from afar, or from the comfort of your home.
What is an EX-View CCD camera, What's good or bad about it?
"EX-View" is a sensitivity-enhancement technology developed by SONY to improve light sensitivity of its CCD by a factor of two for visible light and a factor of four for near-infrared wavelengths.
Rugged Marine has Ex-View capable cameras - ask an Engineer!
EX-View is a proprietary SONY technology in which the P/N junction of each photodiode in the CCD matrix is specially fabricated to have much better photon-to-electron conversion efficiency. In addition, each photodiode (representing one pixel in an image) has a microscopic lens fabricated over it to better capture and focus light onto the active semiconductor junction. This results in an improvement in light sensitivity of 2 times for visible light and 4 times for near-infrared (800 ~ 900 nm) compared to the conventional CCD versions offered by SONY. The lux rating of the EX-View CCD is two times better than the premium SONY “Super HAD” CCD for both visible and near-infrared wavelengths.
What is Super HAD CCD camera?
Super HAD CCD is a trademark of Sony Corporation. The Super HAD CCD is a version of Sony's high performance CCD HAD (Hole-Accumulation Diode) sensor with sharply improved sensitivity by the incorporation of a new semiconductor technology developed by Sony Corporation.
Most Rugged Marine cameras come with SONY SUPER HAD CCD's!!!
Efforts for more pixels and smaller size for CCD have resulted in a smaller aperture area of sensor, presenting the problem of lower sensitivity. To improve this, a lens has been provided on the top of the sensor for focusing, which increases the virtual aperture area of the sensor for higher sensitivity. That is what is called the on-chip micro-lens. Sony, the first to adopt it for the CCD image sensor, has thus successfully achieved higher sensitivity.
This "Super HAD CCD" optimizes the shape of on-chip micro-lenses in order to minimize the invalid area between micro-lenses on each pixel, which thereby minimizes the lost incident light. By doing so our product has been improved the sensitivity per unit of area, despite reducing the unit pixels.
Why is an IR Cut Filter in Color Cameras necessary?
An IR filter, or IR cut filter - is a color filter blocking the infrared light. There are several good reasons for using an IR-cut filter. Using a color camera to achieve realistic colors in white light requires an IR-cut filter. The color spectrum seen by the human eye is quite limited compared to the spectrum seen by a CCD camera. Especially, in the near infrared region of the spectrum the difference in sensitivity is significant. This is important to know since many light sources, including the sun, emit infrared light. A CCD color camera in daylight without an IR-cut filter will therefore see a significant amount of infrared light resulting in strange colors. Another reason for using an IR-cut filter is the limited color correction for many lenses. It is difficult to design imaging optics covering both the visible spectrum and the near infrared spectrum at the same time. Therefore, many lenses have different depth of focus for the visible and the infrared spectrum. Anyway, the IR-cut filter cuts away a significant amount of the overall collected light and thereby affects the sensitivity in a negative way. In general, color cameras are one factor less sensitive compared to monochrome (depending on the CCD chip). This is primarily due to the IR-cut filter.
What is a CMOS camera. What is it different from a CCD camera?
CMOS sensor is a kind of sensor that is normally 10 times less sensitive than a CCD sensor.
As human eye can see an object under 1 lux illumination (full moon night ). CCD sensors normally will see better or as good as the human eye in the range of 0.1 ~3 lux and are 3 to 10 times more sensitive then a CMOS sensor.
What is an Infrared (IR)LED ?
A light-emitting diode (LED) is a semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400 nanometers). Some LEDs emit infrared (IR) energy (830 nanometers or longer); such a device is known as an infrared-emitting diode (IRED).
An LED or IRED consists of two elements of processed material called P-type semiconductors and N-type semiconductors. These two elements are placed in direct contact, forming a region called the P-N junction. In this respect, the LED or IRED resembles most other diode types, but there are important differences. The LED or IRED has a transparent package, allowing visible or IR energy to pass through. Also, the LED or IRED has a large PN-junction area whose shape is tailored to the application.
Benefits of LEDs and IREDs, compared with incandescent and fluorescent illuminating devices, include:
- Low power requirement: Most types can be operated with battery power supplies.
- High efficiency: Most of the power supplied to an LED or IRED is
- converted into radiation in the desired form, with minimal heat production.
- Long life: When properly installed, an LED or IRED can function for decades.
How do mechanical day and night cameras work?
These cameras incorporate IR cut filters which automatically move over the CCD sensor for daytime(color) usuage, to prevent IR light to the CCD. At night time, the filter will be removed automatically to bring in IR right to the CCD, and maximize the low light sensitivity with black and white image.
What are Wide Dynamic Range (WDR) Cameras?
Wide Dynamic Range(WDR) Technology uses two shutter speeds in alternative video fields, high and normal, and combines these two fields into one frame. It allows every detail to be captured accurately even if one portion is bright while other portions are dark. As a result, combined fields yield a frame of high quality images. Below is a comparison of camera technologies with its video images of Regular, Backlight Compensation (BLC), and Wide Dynamic Range.
There are two factors that govern the selection of cable:
- the location of cable runs, indoor or outdoor
- the maximum length of the individual cable runs
Video coaxial cable is designed to transmit maximum signaling energy from a 75 ohm source to a 75 ohm load with minimum signal loss. Excessive signal loss and reflection occurs if cable rated for other than 75 ohms is used. Rugged Marine only sells 75 Ohm cable. Cable characteristics are determined by a number of factors (core material, dielectric material and shield construction, among others) and must be carefully matched to the specific application. Moreover, the transmission characteristics of the cable will be influenced by the physical environment through which the cable is run and the method of installation.
Use only high quality cable and be careful to match the cable to the environment (indoor or outdoor). Solid core, bare-copper conductor is best suited to video applications, except where flexing occurs. In locations where the cable must be continuously flexed (i.e., when used with scanners or pan & tilts), use cable intended for such movement. This cable will have a stranded wire core. Use only cable with pure copper stranding. Do not use cable with copper-plated steel stranding because it does not transmit effectively in the frequency range used in CCTV.
The preferred dielectric material is foam polyethylene. Foam polyethylene has better electrical characteristics and offers the best performance over solid polyethylene, but it is more vulnerable to moisture. Use cable with solid polyethylene dielectric in applications subject to moisture.
In the average CCTV installation, with cable lengths of less than 750 feet (228 m), RG59/U cable is a good choice. Having an outside dimension of approximately 0.25 inches, it comes in 500-and 1,000-foot rolls.
For short cable runs, use RG59/U with a 22-gauge center conductor, which has a DC resistance of about 16 ohms per 1,000 feet (304 m). For longer runs, the 20-gauge variety which has a DC resistance of approximately 10ohms per 1,000 feet will work well.
In either case, cables with polyurethane or polyethylene as the dielectric material are readily available.
For installations requiring cable runs between 800 (244 m) and 1,500 feet (457 m), RG6/U is best. Having the same electrical characteristics as RG59/U, its outer dimension also is about equal to that of RG59/U. RG6/U also comes in 500 and 1000-foot rolls, and it may be obtained in a variety of dielectric and outer-jacket materials. Due to its large-diameter center conductor of about 18 gauge, RG6/U has a DC resistance of approximately 8 ohms per 1,000 feet (304 m) and can deliver a signal farther than RG59/U.
Use RG11/U to exceed the capability of RG6/U. Once again, the electrical characteristics of this cable are basically the same as the others. The center conductor can be ordered in 14-or 18-gauge sizes, producing a DC resistance of approximately 3-8 ohms per 1,000 feet (340 m). Being the largest of the three cables at 0.405 inches, it is more difficult to handle and install.RG11/U cable usually is delivered in 500 and 1000-foot rolls.
Because of special applications, variations of RG59/U, RG6/U and RG11/U frequently are introduced by manufacturers.
Due to changes in fire and safety regulations throughout the country, Teflon and other fire-retardant materials are becoming more popular as outer-jacket and dielectric materials. In case of a fire, these materials do not give off the same poisonous fumes as PVC-type cables, and therefore, are considered safer.
For underground applications, direct burial cables, made specifically for that purpose are recommended. The outer jacket of this type of cable contains moisture-resisting and other materials that protect the cable, allowing it to be placed directly into a trench.
With numerous choices available, finding the right video cable for each camera application should be easy. After the installation has been properly assessed, read the equipment specifications and complete the appropriate calculations.
Although coax cable has built-in losses, the longer and smaller the cable is, the more severe the losses become; and the higher the signal frequency, the more pronounced the losses. Unfortunately this is one of the most common and unnecessary problems currently plaguing CCTV security systems as a whole.
If, for example, your monitor is located 1,000 feet (304 m) from the camera, approximately 37-percent of the high frequency information will be lost in transmission. The unfortunate aspect of this condition is that it is not obvious. You cannot see information that is not there and may not even realize that information has been deleted. Because many CCTV security systems have cable runs that exceed several thousand feet, unless you are aware of this characteristic of cable, your system may be providing a seriously degraded image.
So, if your cameras and monitors are separated by lengths greater than 750 feet (228 m), you should check to make certain that some provision has been made to guarantee the video signal's transmission strength. One common method to produce longer runs is to purchase Video Baluns that change the Ohms level over to CAT-5 wiring. Unpowered Baluns can carry the signal up to about 1000 feet, and powered versions can typically extend the video signal up to as much as 3 miles or more. Check with your Rugged Marine Engineer to see what method is right for your CCTV system.
The math is complicated so we do it for you - just fill in the blanks
& you get your answer immediately!
Bright spot smears on monitor
Cameras are designed to view light reflected from the scene being viewed. When you have a bright light source in the picture, it may produce a bright white spot on the monitor and a vertical white line through it. This is a problem especially at night.
Solution: Reposition camera to avoid bright light sources in the scene.
Bright background, dark foreground
A bright area in the picture causes the iris to close or the imager to reduce gain. This causes the unlit area to appear darker.
Solution: Use a camera with backlight compensation or reposition camera to avoid bright background and/or illuminate foreground to even lighting of scene.
Picture rolls when switcher changes
Line locked cameras get synchronization from the AC power supply they use. If camera power supplies are out of phase during switching, you will notice a rolling between frames from one camera to another. This can be confusing to the person monitoring the system. It can also create problems for your time lapse recorders.
Solution: Power cameras from the same phase on your electrical panel or use cameras that have a phase adjustment control.
Picture is snowy or snowy bars roll on screen
The coax cable is picking up electrical, magnetic, or radio interference. This problem is very prevalent when using inexpensive cable.
Solution: Re-route cables away from problem area and use only good quality cable.
Picture tears horizontally or snowy bars roll
The system is suffering from a ground loop(s). A ground loop is caused when camera and monitor are powered from sources using different grounds with different ground potentials. If a path for current flow (other than the coax) exists, ground loops are possible. A difference of a few millivolts can cause a ground loop. Ground loops are not predictable and may appear or disappear after the system is installed.
Solution: Install a ground loop corrector or power all camera from the same source as the monitor.
No picture at the monitor
An open or short in the cable is the most common cause. Breaks in the center conductors are caused by excessive pulling or bending, shorts are usually caused by improper connector installation.
Solution: Disconnect the cable at both ends and check with a meter.
1) From center pin to outer connector should read open. If it reads shorted, reinstall the connector. If it still reads shorted, read cable directly. If this fails and cable still reads shorted, replace cable.
2) Short one end (pin to outer), meter from other end, it should read shorted. If it reads open, check the cable directly. If the cable reads open, replace the cable.
Monitor has "ghosts"
When a video signal is not properly terminated it reflects back on itself, resulting in secondary images called "ghosts." Unless you pass the signal onto another video product, the signal needs to be terminated.
Solution: Make sure "Hi-Z/75 ohm" switch is in "75 ohm" position unless looping the video signal on to another device.
ABERRATION - Any inherent deficiency of a lens or optical system. Aberrations are responsible for imperfections in shape or sharpness of the image.
AGC - Automatic Gain Control, an electronic circuit that amplifies the video signal when the strength of the signal falls below a given value.
ALC - Photometric control, measures light intensity. Determines the iris reaction sensitivity. Sensitivity is increased when the potentiometer is turned towards PEAK, and decreased when turned towards AVERAGE.
ANGLE OF VIEW - May be expressed in Diagonal, Horizontal, or Vertical. Smaller focal lengths give a wider angle of view.
APERTURE - The opening of the lens that controls the amount of light reaching the surface of the pickup device. The size of the aperture is controlled by the iris adjustment.
APERTURE SCALE - The aperture scale is referred to as an F-number. The international aperture scale is: F1, F1.4, F2, F2.8, F4, F4.6, F8, F11, F16, etc.
ASPHERICAL LENS - A lens one or more of whose elements has a non-spherical surface. Aspherical surfaces are shaped to reduce the spherical and other aberrations.
AUTO-IRIS LENS - A lens with an electronically controlled iris. This allows the lens to maintain one light level throughout varying light conditions.
BACK FOCUS - A term used to describe the relationship of the distance of the lens to the image device. This distance is critical to maintaining the proper depth of field through changing focal lengths and varying light conditions. The correct back focus is normally achieved by adjusting the image pick-up device on the camera itself.
BLC - Back light compensation. A function of the camera that compensates for excessive light directed at the camera, which causes the video to bloom or the images in front of the light to be unusable.
CAMERA FORMAT - The approximate size of a camera image pickup device. This measurement is derived from the diagonal line of a chip or the diameter of the tube. Currently there are five format sizes in the CCTV industry: 1", 2/3", ?", 1/3" and, ?"
C-MOUNT - An industry standard for mounting a lens to a camera where a 1? x 32 thread is employed and the distance from the image plane is 17.52mm from the shoulder of the lens. A C-mount lens may be used CS-mount camera with the use of a 5mm-adapter ring.
CS-MOUNT - A relatively new industry standard for mounting a lens to a camera where a 1" X 32 thread is employed and the distance from the image plane from the shoulder of the lens is 12.52mm. A CS-mount lens may NOT be used on a C-mount camera.
DEPTH OF FIELD - The regions in front of and behind the focused distance where the image remains in focus. With a greater the depth of field, more of the scene near to far is in focus. Lens aperture and scene lighting will greatly influence the D.O.F.
EXTENSION TUBES - Various size spacers used between the camera and lens to reduce the Minimum Object Distance. Not recommended for use with zoom lenses due to the loss of tracking ability.
F-NUMBER - Indicates the brightness of the image formed by the lens, controlled by the iris. The smaller the F-number the brighter the image.
F-STOP - A term used to indicate the speed of a lens. The smaller the F-number the greater amount of light passes through the lens.
FIELD OF VIEW - The horizontal or vertical scene size at a given length from the camera to the subject.
FOCAL LENGTH - The distance from the center of the lens to a plane at which point a sharp image of an object viewed at an infinite position. The focal length determines the size of the image and angle of FOV seen by the camera through the lens. This is the center of the lens to the image pickup device.
HUNTING - An industry term used to describe a auto-iris lenses inability to stabilize under certain light conditions.
IRIS - A mechanical diaphragm which can be controlled manually or automatically to adjust the lens aperture.
LENS FORMAT - The approximate size of a lens projected image. In most cases the lens will project a image slightly greater than the designated image size to insure the pickup device is completely covered. It is recommended that camera and lenses are the same format size. A lens a larger format size can be used on a smaller format camera, however a smaller format lens should never be used with a larger format camera.
LENS SPEED - Refers to the lens aperture or its ability to transmit light. This is measured in F-stops.
LEVEL CONTROL - Used to set the auto-iris circuit to a video level desired by the user. Turning the level potentiometer towards the HIGH position will open the iris allowing more light to pass through the lens, towards the LOW will close the iris allowing less light to pass through the lens.
MANUAL IRIS LENS - A lens with a manual adjustment to set the iris opening (aperture) to a fixed position. This type lens is generally used in fixed lighting conditions.
MINIMUM OBJECT DISTANCE (M.O.D.) - The closest distance a given lens will be able to focus upon a object. Generally the smaller the focal length the shorter the M.O.D. This distance can be altered with use of extension tubes.
PINHOLE LENS - Lenses used primarily in covert applications where the camera/lens must remain out of sight.
PRE-POSITION LENSES - Pre-position lenses are specially designed lenses with extra mechanical/electrical components to allow for computer interfacing. This function allows the lens (when used with the appropriate controller) to feedback to the controller information relevant to zoom and focus propositioning allowing the controller to quickly scan to a pre-selected scene, arriving in focus at the proper zoom point without operator intervention.
SPOT FILTER - A neutral density filter paced at the center of one of the elements (or on an iris blade) to increase the high end of the F-stop range of the lens.
TELEPHOTO - Telephoto is a term used to describe lenses that have a high focal number causing the reproduced image to appear larger than human eye reproduction.
TRACKING - A zoom lenses ability to remain in focus throughout the entire zoom range.
VARI-FOCAL - A low cost version of a zoom lens designed to meet installers needs for versatility. This lens does not have the ability to track from wide to telephoto.
VIDEO TYPE LENS - An auto-iris lens with internal circuitry for processing of the video signal which controls the iris movements.
ZOOM LENS - A lens with the ability to change its focal length manually or through the use of a controller to cover a variety of needs.
ZOOM RATIO - The ratio of the starting focal length (wide) to the ending focal length (telephoto) of a zoom lens. A 10X zoom will magnify the image at the wide end by 10 times. Examples of a 10X zoom lenses; 8mm~80mm, 12mm~120mm.