Linglung series lenses will all go through flange back adjustment based on M4/3 standard before shipping, but flange back distance can vary on different cameras. If the flange back distance is incorrect, the camera will not focus at the correct distance. Linglung series has fast adjustment structure which is placed between aperture ring and lens mount.
When adjusting, please follow the steps below.
1、Prepare your object. You can use the "Siemens Star Test Chart" and make sure the printing is clear.
2、Attach the lens to the camera;
3、Adjust the aperture to the max at T2.9;
4、Zoom in to the long focal length (24mm or 70mm);
5、Adjusting the focus ring until the object is at its sharpest.
6、Zoom out to the wide angle (10mm or 20mm);
7、Please make sure the focus ring remains unchanged and calibrate the object to the sharpest only through adjusting the back flange ring, if the focus ring changes, please start again from the fourth step.
8、Repeat Step 3-7 for two to three times. When the best focus stays in a same position in all different focus distance, the calibration finishes. The situation may vary in different cameras, and please repeat the steps to make sure the focus is sharp in both wide angle and long focus distance.
9、Lock the screw rod on the back flange distance after calibrating. Theoretically the back flange need to re-calibrate after changing to other cameras