The luminosity histogram is generally the more commonly used because it measures total brightness and can therefore be used to keep tabs on your exposure, which is what I’ll be discussing here.

The histogram graphs –- one for brightness, one for color — are another set of tools that can help you determine if your chosen exposure settings hit their mark.

Adjust the exposure time to change the histogram peak location. Flat darks are dark frames for your flats — just like you use a master dark to calibrate your lights.

Your camera will pick one and thus over- or underexpose the other. Some strategies: - look at the picture and histogram and apply exposure compensation and retry ...