Diffusion Filter
A filter that scatters a small proportion of the light passing through it, lowering contrast and blooming highlights into a soft glow.
Measured in
grade (1/8, 1/4, 1/2, 1)
In depth
Marketed as black mist, pro-mist or soft filters, these work by suspending fine particles in the glass. Black mist versions lift highlights while keeping shadows relatively clean, which digital sensors — with their very abrupt highlight roll-off — often benefit from. The effect is genuinely optical and cannot be exactly reproduced in post, because the glow is created before the sensor clips.
Examples in practice
A 1/4 black mist filter turns hard practical lights in a night portrait into gentle halos rather than sharp points.