Micro-contrast is the contrast between very small, adjacent details in an image—essentially fine tonal separation at a local level. It strongly affects how sharp, crisp, and detailed a photo appears.

By contrast, regular or overall contrast usually refers to tonal separation across the whole image, from shadows to highlights. That relates more to the scene’s or image’s global tonal range.

So an image can have:

• high micro-contrast but low overall contrast: fine detail looks crisp even if the scene has fairly uniform tones
• high overall contrast but low micro-contrast: strong dark/light separation overall, but fine detail looks soft

Micro-contrast is influenced by lens quality, diffraction at very small apertures, and digital capture factors such as anti-aliasing/low-pass filters, which can soften fine detail. That’s why it is often associated with perceived sharpness rather than just “contrast” in the usual sense.

In practical terms, micro-contrast matters because it helps images look more detailed and three-dimensional, even when resolution alone doesn’t tell the whole story.