Calibration Frames

Calibration frames remove the camera's fixed-pattern noise and optical vignetting from your lights. Three types matter most:

• Darks – same exposure time and temperature as your lights, lens cap on.
• Flats – an evenly lit field that captures vignetting and dust shadows.
• Bias – the shortest possible exposure, used to subtract read noise.

Shoot flats right after each session while the optical train is still untouched. Store darks in a library by temperature and duration so they can be reused. Capture a handful of each type and let your stacking software build a master frame from them – the background uniformity of the final image improves noticeably.