Ask Joe Mechanic - Back Up Cameras and Blind Spot Monitors

Back up cameras have existed for quite a few years and have recently become more common on many types of vehicles.  A federal law will require that all new vehicles produced after 2015 are equipped with a back up camera.  Back up cameras were originally introduced for use on motorhomes where rear visibility is severely limited and also because the owner may be towing a car or trailer behind the motorhome with little to no visibility of the towed object.

            Adding a backup camera is a simple process for many manufacturers, since they already equip newer vehicles with a screen used for navigation or playing DVDs which can double as a backup monitor. They are now offered as standard or optional equipment on many SUVs, trucks and vans, and on many higher-end automobiles. On these vehicles, the camera is wired so that when reverse is selected, the display will show the camera view and switch back to GPS or DVD when the vehicle is taken out of reverse.

Most cameras use a wide angle or a fisheye lens to give a wider view of the entire rear of the vehicle. Blind spot alert cameras also use this type of lens. With a rear view camera, the display automatically does a horizontal mirror image flip so that you can get the correct side displayed on the viewer. With these lenses, you get an uninterrupted view of the entire rear of the vehicle.

I want to give you some simple information in easy to understand terms in case you are choosing to purchase a back up camera kit to install on your vehicle. One of the most important features to consider in the purchase of a camera is whether or not it has an automatic switching feature.  Meaning that the display comes on as soon as you put your vehicle into reverse. This is quite simply accomplished if the system is so equipped, by connecting a single wire into the back up light circuit. Additionally, this type can be turned on manually by pushing a power button or a wireless remote if so equipped. Some of the advanced systems can even operate multiple cameras.

The second important feature is the ability to provide the mirrored or reverse image. This means that the picture on the display will duplicate what you would see in the rear view mirror. Some high-end systems actually allow you to select between normal and mirror images. Many of the low priced systems, such as many of those offered on Ebay, do not have this feature. If it is not listed in the features, assume it is not there and do not consider buying it.

A wide-angle field of view is also very important. Low priced systems do not offer more than a 60 or 90-degree view.  While this may be okay for a small automobile, it is not nearly sufficient for a medium to large vehicle. Look for a system that offers 120 to 150 degree field of view with a 1/3-inch image sensor. A camera that offers 180 degrees or more is also not recommended, as it will give a distorted view.

There are two types of sensors, CCD (charge coupled device), and CMOS (complementary metal oxide semiconductor). The CCD image sensor is the preferred type as it offers greater clarity than CMOS. Sharp and Sony produce the highest quality CCD sensors, check to see who manufactures the sensors for the system you are considering.

Also, remember that the camera is mounted on the exterior of the vehicle and is therefore exposed to all sorts of weather conditions. The cameras are generally made to withstand it, but it is important to make sure that the cables and connectors are weather resistant. Many low-end systems use RCA type cable connectors similar to your TV or VCR; these connectors are not weather resistant.  Do not buy a system that will place these in exposed areas!  However, this type connector is okay, and is actually better for use in the interior of the vehicle.

Infrared night vision is also an important feature that can be easily misunderstood. Infrared gives the ability to see in very low or no light situations, which is quite important for night use. On a high quality system, the infrared LEDs turn on automatically when the unit measures the background light below a certain level.  Infrared light is not visible to the human eye as it is out of our vision spectrum, but the camera is designed to make use of it. A good camera will give at least 20 feet and ideally 30 to 50 feet of night vision range.  Don’t buy a system that gives less than 15 feet, as that is less than one car length.

One of the most serious questions to consider is not whether the system will work on your vehicle.  Most systems are designed to by universally compatible, but, how long and how well will they work? Many of the lower priced units do not come equipped with a voltage regulator. If a unit does not have one of these, it is at the mercy of a constantly varying voltage from the vehicle’s electrical system.  This factor will either cause eventual damage to the system, or at least cause serious variation in picture quality. Some high quality cameras are even designed to be adjustable for vehicles that have 24 or even 32-volt systems such as buses and heavy trucks.

If you are purchasing a system with an audible monitoring, make sure that the audible pickup is weatherproofed.  LCD monitors are the preferred type as they offer full color as opposed to the CRT screen’s gray or green screen. For best picture quality, always select a TFT-LCD type monitor. For larger vehicles, a five-inch or larger monitor is preferable, whereas in smaller vehicles or where space is limited, a three or four inch screen is sufficient.

There are four basic types of cameras; the type of mounting mostly determines the difference. Surface mounts are best suited for larger vehicles were it could be mounted on any flat or nearly flat surface.  The camera should be aimed downward at about a thirty-degree angle.  For pickups, cars and smaller SUVs the flush mounted camera is the preferred choice. This camera gets mounted through a hole in the back of the vehicle and should be set at a slightly downward angle. License mount cameras can be mounted on the license plate bracket as long as the camera can be adjusted to the proper angle. There are also side and forward facing cameras for those specific applications.

A hard-wired system will always offer a higher quality picture than a wireless system, as these are susceptible to interference from radio, TV, and cellular transmitters. Most of the wireless systems sold on Ebay will turn out to be a complete disappointment. Hopefully, armed with this information, if you go shopping for a camera, you will be able to find a system that suits your needs and budget, and gives you the kind of service that you deserve for your hard earned investment.