In this sense it's "Feineinstellung" or "Abstimmung" for "tuning" and "kalibrieren" for "to calibrate". The two are different, however. If you could give a more concrete example of the kind of text you need to write, I can give a more detailed answer.

Wir mussen erst die Brilles Kamera kalibrieren. -> Zunächst muss die Linse der Kamera kalibiriert werden. This means you do a one-time calibration to offset differences in the manufacturing process of the camera and of the lens by comparing it with standardized values. Brille = glasses you wear on your nose Linse = lens This camera needs to be calibrated for its surroundings by using a specific lighting decice. Diese Kamera muss auf die Lichtverhältnisse der Umgebung eingestellt werden, indem eine genormte Lichtquelle benutzt wird. = The differences between a standardized lightning source and the light coming from the surroundings are used to tune the camera to get good photographic results with respect to these surroundings. You can use instead "muss auf die Umgebungsverhältnisse kalibriert werden" if you want to use the camera to measure light intensity, and you want to make sure that one or some standardized light sources always give the same numerical values, and the camera is sensitive to changes in the surroundings like temperature etc. So, again, it depends on what exactly you want to do.