David Mullen ASC
Moderator
No, I said "wider shots" not "wide lenses"...
There are two rules regarding diffusion filters which are somewhat contradictory:
#1 Wider-angle lenses need more diffusion than longer lenses to match sharpness.
#2 Wider shots need less diffusion than close-ups because we expect to see more fine detail in wide shots and don't need to see every pore and flaw in a close-up as long as the eyes look sharp.
The first rule is an objective one about matching sharpness and the second is a subjective one regarding viewer perception. The confusion comes from the fact that wide shots tend to be shot on wider-angle lenses and close-ups tend to be shot on longer lenses. But the reason we use heavier diffusion on close-ups of faces is because our eyes don't demand the same level of detail that we crave when viewing a wide shot of a landscape let's say. We look at a landscape shot and expect to see final detail in leaves of trees, blades of grass, the texture of brick walls, etc. but when we look at a face, an excessive amount of detail and texture in skin, for example, can be unwelcome or at least unnecessary -- we mainly expect things like eyes and eyelashes to be sharp, and strands of hair, but we often don't like seeing too much texture in skin.
There are two rules regarding diffusion filters which are somewhat contradictory:
#1 Wider-angle lenses need more diffusion than longer lenses to match sharpness.
#2 Wider shots need less diffusion than close-ups because we expect to see more fine detail in wide shots and don't need to see every pore and flaw in a close-up as long as the eyes look sharp.
The first rule is an objective one about matching sharpness and the second is a subjective one regarding viewer perception. The confusion comes from the fact that wide shots tend to be shot on wider-angle lenses and close-ups tend to be shot on longer lenses. But the reason we use heavier diffusion on close-ups of faces is because our eyes don't demand the same level of detail that we crave when viewing a wide shot of a landscape let's say. We look at a landscape shot and expect to see final detail in leaves of trees, blades of grass, the texture of brick walls, etc. but when we look at a face, an excessive amount of detail and texture in skin, for example, can be unwelcome or at least unnecessary -- we mainly expect things like eyes and eyelashes to be sharp, and strands of hair, but we often don't like seeing too much texture in skin.