The borescope is an optical device featuring a rigid or a flexible tube with an eyepiece on one end, an objective lens on the other linked together by a relay optical system in between. Such tools find application in inspection jobs where a given area has to be inspected but are inaccessible by other means. Borescopes are either flexible or rigid.

Each type has its own unique advantages, so it's hard to point out clearly which is better, as it all depends on the application. Nevertheless, the rigid borescopes are the more popular type, maybe becuase they are cheaper. Their disadvantage is that their body is static and it won't reach all the places you would like to see.

However, the image quality of rigid borescopes is higher compared to flexible models, plus rigid borescops are easier to use and can spot flaws as small as 0.001. If movement is not your main priority, buy a rigid borescope. Flexible borescopes can be used to access cavities which are around a bend. But at the end, if you can buy both types that will be ideal, otherwise choose according to your specific situations that you are likely to exhibit.

The conclusion is the when choosing a borescope to buy, you must have a clear idea where exactly you will be using it. Once you know the type, then you have to choose the diameter, so that the borescope will be able to enter the smallest hole required. It's always best to plan for some degree of free movement, that's why get a slightly smaller diameter than the allowed minium.

The mangnification of a borescope is a measure of how large and object appears when viewed through the borescope as compared to its actual size when viewed from the same location without the borescope. But the power of magnification doesn't increase automatically if the object that's being viewed moves further away. Borescopes can be used with a digitam camera in order to record the images or view them on a big monitor.

But not all borescopes and cameras are compatible. You should consult with a sales agent or check the manual or internet to see if the two particular models which you have in mind will work properly together. An objective lens with long focal length is requried when you want the image from the borescope to fill up the whole screen.

The focal length on the camera must be at least 35mm. If you have a 3 megapixel camera, then a 3x digital zoom will be fine. And because cameras are not originally designed to support a borescope, make sure there is no over-strain which can lead to structural damage of the devices.