# Stereo right side out of focus

Source: https://forum.modalai.com/topic/1077/stereo-right-side-out-of-focus
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2022-07-01 02:16:50 UTC by 張為超
Replies: 3 · Views: 1073

## 張為超 · 2022-07-01 02:16:50 UTC

Hi, I just find out my right side stereo cameras is out of focus.

![Screenshot from 2022-06-30 11-13-06.png](https://forum.modalai.com/assets/uploads/files/1656640965109-screenshot-from-2022-06-30-11-13-06.png) 

This situation is make me hard to do the camera calibration since the right side image is blurry and hard to detect chess board tag. In fact I tried to perform camera calibration twice and it took me very long time and unfortunately failed in the end.

Is there anyway to fix this problem besides camera calibration? Or a camera calibration with bigger tag would solve my problem (mine is A4 size)? Any suggestion is welcome, Thanks!

## Reply by Guest · 2022-07-01 16:33:38 UTC

The cameras are focused in our lab but can sometimes shift a little during shipping, you can gently twist the camera frontend to change the focus.

## Reply by Dobry Kolacz (ModalAI staff) · 2022-07-01 18:05:15 UTC

![stereo side.jpg](https://forum.modalai.com/assets/uploads/files/1656698005519-stereo-side.jpg) 
Stereo sensors have adjustable lenses. Indicated in the photo is the part that can be screwed in or out to change the focus.

![stereo wrench.jpg](https://forum.modalai.com/assets/uploads/files/1656698191602-stereo-wrench.jpg) 
There are four flat edges around the lens, a 6mm wrench fits perfectly on the flat edges and is the best way to adjust the focus. You can also use tweezers or pliers to adjust the lens, just be careful because you don't want to have the tool slip off and scratch the stereo lens.

When focusing, pay attention to the center of the image, sometimes there can be some blurriness around the edges of the image even when the center of the image is in good focus. As long as the center of the image is in focus, you should be able to get a good calibration.
Try to have both cameras focused to the same point for best results.

## Reply by 張為超 · 2022-07-02 05:58:43 UTC

Thanks for answering me , I will give it a try! If i get any problem I will keep update. Thanks!:blush: