From Burr to Tongue · The Size of a Single Pixel

Photographing five particles · circle = actual size, red = pixels kept by the cutoff

One pixel –Focus margin –

Results by size · measured ÷ actual diameterline = mean, band = 95% range

Vanishes at –Smallest size within ±5% –

Phone height Closer means smaller pixels

Blur σ Lens, shake, demosaicing, compression

Cutoff brightness Particle 0, background 1. Higher = toward background

Noise Random brightness jitter per pixel

Phone main-camera model: 4032 px, 26 mm equivalent, f/1.78, one photo pixel = 2.44 µm on the sensor. Particles are dark discs on a backlit surface, each size measured 40 times at shifted pixel positions. The coffee fines peak sits at 30–40 µm. Click the left panel to reshuffle particle positions.