Reading a histogram

In short: The histogram shows how many pixels of a photo have which brightness: dark on the left, bright on the right. It helps judge whether a picture is under- or overexposed independent of the display.

In more detail: The height of the bars indicates the number of pixels per brightness level. A well-exposed picture usually fills the middle and tails off at the edges.

In detail

• Underexposure: The mountain sits on the left and hits the edge: shadows are crushed.
• Overexposure: The mountain hits the right: highlights are blown and cannot be rescued.
• High-contrast subjects: The histogram fills both sides.
• No “correct” histogram: A snow picture lies right, a night picture left, and both can be correct.
• RGB histogram: Shows colour channels separately and warns of colour loss.
• Exposure compensation: If the picture is too dark set +, if too bright − (blende-und-schaerfentiefe, iso-und-bildrauschen).