Sensor size and image quality

In short: A larger camera sensor captures more light and usually delivers a better image in poor light with less noise and more dynamic range. Size matters more than the megapixel count.

In more detail: Full frame (36 × 24 mm) corresponds to the old 35 mm film. APS-C is somewhat smaller, Micro Four Thirds smaller still, smartphone sensors tiny.

In detail

• Crop factor: With smaller sensors the angle of view appears narrower, for example ×1.5 with APS-C (brennweite-und-bildwinkel).
• Megapixels: Many pixels on a small sensor mean smaller pixels and more noise. For web and print up to A3, 12–24 MP suffice.
• Dynamic range: The difference between the brightest and darkest discernible area is greater with large sensors.
• Smartphones: Compensate small sensors with software (computational photography).
• Depth of field: Large sensors make background blur easier (blende-und-schaerfentiefe).
• Price and weight: Larger sensors require larger lenses and cost more.