A borescope allows you to visually inspect areas that were previously concealed from view, without ever needing to dissemble or break anything. Because borescopes have consistently been dropping in price, it is no surprise that these handy and non-invasive remote viewing tools have snaked their way into more and more industries.
Not that long ago, borescopes were almost exclusively used in large-scale industrial settings, such as aerospace engineering, arms manufacturing, and the maintenance of heavy industrial equipment. Now, though, inexpensive borescopes are within easy reach for small businesses, self-employed tradespeople, and even hobbyists.
People whose jobs are made easier with the help of a borescope include plumbers, home inspectors, HVAC technicians, pest control professionals, and auto mechanics — and the areas they are inspecting for quality control reasons or to diagnose a problem are extremely diverse.
Sometimes, the area you want to inspect with a borescope is tricky or impossible to reach without taking structures or components apart, but very close by. If you want to take a peek below your kitchen cabinets to see if any pests are present, for instance, you probably won’t need a very long probe. Should you, on the other hand, be planning to use a flexible borescope to get a closer view of the depths of a sewage pipe, the borescope’s optic cables will need to be a whole lot longer.
How far can you see with a borescope, then?
The answer depends on the working length of the cable and probe, but also on the borescope’s focal length. Let’s examine that further!
How Far Can You See with a Cheap Basic Borescope?
People who are looking to buy a basic borescope for personal use will likely head straight for Amazon and start shopping around for an inexpensive USB borescope. These borescopes feature a USB port to allow them to connect straight to an Android phone, iPhone, or laptop. The fact that they do not come with built-in LCD screens is a big reason for their cheap price, but the quality of these borescopes still varies significantly.
The most inexpensive borescopes will set you back less than $50 — but how far can you see with them?
Here’s a look at some of the most popular borescopes on Amazon today:
How Far Can You See with a Professional Borescope?
Borescopes designed for a wide variety of purposes are now available on the market, and their maximum probe length — which determines how far you can see with the borescope — depends on the type of borescope you are looking at.
Rigid borescopes have rigid probes that cannot bend. These probes may be attached to much longer cables, but rigid borescopes cannot be used to see around corners, and they can’t be fed into U-bends or other curved pipes. Rigid borescopes can be helpful for situations in which gravity would make it hard to use a flexible borescope, such as to inspect chimneys or areas within an attic. They are also often used to inspect guns. Rigid borescopes generally have probes of up to 26 inches (66 centimeters).
Flexbible borescopes with articulating tips — also often simply called articulating borescopes — allow users to pivot the camera 360 degrees. These cameras can, in other words, make full turns, often with the help of a joystick control. This feature adds versatility, but it does limit the length of the cable. The longest articulating borescopes have a cable length of 49 feet, which translates to 15 meters.
Flexible borescopes that do not have an articulating tip can have much longer cables, allowing users to inspect areas that are further away. These non-articulating viewing instruments can be shipped with cables with a length of up to 98 feet (30 meters).
Other options are available for situations that require a much longer cable length to make it possible to inspect, for instance, long sewage pipes, however. Push cameras are remote viewing tools that are similar to borescopes. These are waterproof cameras connected to a so-called push rod, or a long cable. Many push cameras feature 120-meter (or 400-feet) long push rods, while the longest push rods can reach up to 200 meters (that’s an impressive 656 feet!).
What Is the Focal Length of a Borescope?
A borescope’s cable length determines how far the camera can physically reach, making it a key consideration if you are trying to find out how far you can see with a borescope. It is not the only factor you need to take into account, however.
A borescope’s focal length determines how far away, or close up, an object or area can be from the borescope while still allowing the user to get a sharp image.
Near-focus borescopes have a focal range of 2mm to 20mm, middle-focus borescopes have a focal range of 10mm to 50mm, and far-focus borescopes are advertised as having a focal length of 50mm to “infinity” — although you shouldn’t necessarily take that literally. Some borescopes can additionally be focused manually, although this means investing more money.
The Verdict: How Far Can You See with a Borescope?
Even the most basic borescopes feature reasonably long cables of 3.5 meters (11.5 feet) to 15 meters (50 feet), making them perfectly adequate for most everyday uses, including engine inspections and plumbing applications. Professional articulating borescopes may have cables of up to 15 meters (49 feet), while non-articulating borescopes can have cables that measure up to 30 meters (98 feet).
Longer cables are not always better, however — if you are inspecting an engine or a HVAC unit, a very long cable will only get in the way of your job.