In a sense, binoculars are as sensitive as cameras. Indeed, binoculars don’t have image sensors or circuit boards. However, the fact that the two barrels have to be perfectly aligned makes manufacturing binoculars more difficult.
Compared to telescopes, a big advantage binoculars have is to be able to view something stereoscopically.
Here, I would like to familiarize you with “collimation” and “optical axis”, so you can understand how much effort manufacturers go through in order to provide you with excellent binoculars.
Binoculars are basically a pair of refractor telescopes joined together. Collimation refers to the process of aligning all the lenses to the right position. The optical path of light needs to be adjusted to the center of each lens.
Unlike a telescope, binoculars have two prisms in each barrel to get an upright image. Normally the objective lens actually consists of two lenses, and the eyepiece has three lenses. You can imagine how much sensitive work is needed to adjust the optical path to come through the exact center of all the components.
With binoculars, collimation also means the alignment between the two barrels (telescopes). As most people use “collimation” as “adjusting optical axes,” I will explain it here.
As you can see, binoculars have two barrels. When manufacturers join the two barrels, they must be perfectly parallel. In other words, the image formed through both barrels has to come together as a single image.
It takes special equipment and skilled technicians to collimate binoculars perfectly.
In addition, the two barrels need to be joined together so precisely that the alignment stays the same even when you adjust the IPD (Interpupillary Distance).
Finally, all the lenses and prisms have to be fixed firmly after adjusting the alignment.
If the optical axes of the barrels are slightly different, the image from each barrel also becomes a little different.
If collimation is even slightly outside of the acceptable range, your brain will try to compensate for it, which can give you headaches and nausea.
As is often the case with cheap binoculars, they are shipped from the manufacturer out of collimation because they don’t have the technical ability or they simply don’t want to take the time.
Famous brands such as Zeiss, Leica, and Swarovski continue to make binoculars despite modest sales because their customers want the best there is and appreciate their focus on quality control.
What you should do if your binoculars are out of collimation.
Binoculars are vulnerable to shock. If you drop your binoculars, they are likely to get out of collimation.
In that case, the best way is to contact customer service and ask them to repair the binoculars. They can usually provide you with an estimate for the repair.
Because of the difficulty level, I don’t recommend that you try to collimate your binoculars by yourself. Some binoculars have tiny screws to adjust the prisms, but it usually takes a skilled technician and much patience.
Newer binoculars are not easy to take apart because the body is covered with rubber armor, and some parts are attached with strong glue.
So, I strongly advise you to use the neck strap every time you (or a friend) use your binoculars.