What are bias frames, and why do they matter? These are ultra-short exposure images taken with the lens cap on that capture the baseline electronic noise generated every time your camera reads data from the sensor.
Unlike dark frames, bias frames have almost zero exposure time and isolate the sensor’s readout noise. Capturing many (50 or more) and averaging them into a master bias frame helps improve the precision of your entire calibration process.
Even if your camera has low readout noise or is cooled, bias frames remain a best practice for professional-grade astrophotography.
