- Purpose
- fix the pattern noise the sensor produces, the inherent noise of the electronics of the sensor
- Where
- complete darkness
- When
- camera has to be outside long enought to become same temperature as the light frames are going to be
- How
- cap on the sensor
- Aperture settings
- not relevant because no light reaches the sensor since there is the cap on it
- Exposure time
- the shortest possible
- ISO
- same as light frames
- Count
- at least 50
- Purpose
- correct hot pixels on the image sensor and heat noise
- Where
- complete darkness
- When
- with the light frames, they must match the temperature of the light frames were shot
- How
- cap on the sensor
- Aperture settings
- not relevant because no light reaches the sensor since there is the cap on it
- Exposure time
- same as light frames
- ISO
- same as light frames
- Count
- 25-30% of the number of light frames
- Purpose
- fix the vignetting effect that comes with lens-based systems
- fix dust on sensor or lens
- Where
- the same place and position of light frames
- When
- doesn't matter
- How
- take pitcures of a flat white surface, a piece of paper should work
- Aperture settings
- same focal point and aperture as light frames
- Exposure time
- as long as it's needed to make the bump on the histogram of the image to reach halfway of the histogram
- ISO
- same as light frames
- Count
- at least 50