The lens on FPV camera can often get loosened due to vibration or crashes. In this tutorial I will show you how to focus FPV camera lens in a few simple steps.
How to Adjust FPV Camera Focus
The lens has a threaded shaft itself, and there is a lock ring (aka lock nut) at the base of the lens to stop it from moving once secured.
To adjust the camera focus, you just need to screw the lens in or out until you find the sweet spot.
The first thing you want to do is to unscrew and loosen the lens from the camera. You should hold your camera facing away from you in this tutorial.
By turning the lens clockwise, both the lens and lock nut should come loose at the same time. If not, try loosening just the lock nut first by turning it clockwise.
For standard size cameras, you can just use your fingers to turn the locknut. With the smaller lenses on the Micro cameras, you might find it easier with a pair of tweezers.
Make Sure Lock-nut Isn’t Broken
Before proceeding to focus FPV camera lens, it’s wise to check if the lock nut is actually broken. It’s the one thing that holds the lens in place and keeps it in focus, if it’s broken your camera will soon become out of focus again as the lens loosens.
Steps to Focus FPV Camera
Finding Good Reference Objects
You can focus your camera using any object as reference. Find something with fine detail like branches, fences, tiles etc, that allow you to more easily see the differences in the image.
I personally find it much easier and more accurate using a focus test pattern (camera focus chart). You can print it on a piece of A4 paper: https://goo.gl/ckdyvV
The object distance you focus on matters. If you focus your camera with objects too close, the camera might look blurry with object further out. And vice versa.
If you are focusing on the test pattern, put it about 3 meters away (10 feet).
If you are using the surrounding as reference, you want to stand further away, around 10 meters (30 feet). As long as you can see clearly at this distance, you should be fine when flying FPV.
Turn the Lens and Adjust Focus
Now connect your camera either directly to a monitor, or to a VTX and display the image through a pair of FPV goggles. It’s best to do this outdoor in good lighting.
Loosen the lens a couple of full turns, and turn the lock nut slightly away from the camera so you can screw in the lens deeper later on,
Now tighten the lens but very slowly.
You should notice that the image will get clearer and clearer, until a point where it will begin to become more and more out of focus again. You should go back and stop at that point where it’s in perfect focus.
With a focus test pattern, you want to stop at the point where the blurry center becomes as small as possible.
Here is a quick video showing the focusing process through DVR.
Now, hold the lens with one hand, and no matter what, don’t move it! It can be helpful to mark the camera case and lens where they meet, to help alignment during tightening.
Turn the lock ring with the other hand towards the camera until it touches the base.
Note that when doing this, the lock ring is usually not tight enough to hold the lens in position. So what you need to do, is to hold the lock ring in place with one hand, and unscrew the lens back up just a bit (40-50 degree, 1/8 of a turn). Now release the lock ring, and turn both the lens and lock ring inward, so the lock ring snugs up against the base, and the camera should also come back in focus.
This might not work the first time and you have to go back and adjust the position of the lock ring. Just keep repeating until you get it just right.
You definitely want to make sure the lock nut is fitting tightly against the base. Otherwise it can move with the lens during flight or in crashes.
Still Out of Focus?
If none of the above helped, and you are still getting a blurry image from your FPV camera, chances are you have a faulty camera. It could either be the lens, or the image sensor. Try a different lens see if it works.
Sometimes dust and water can get trapped inside the lens too which might require a good clean or replacement.