What is EFCS (Electronic Front Curtain Shutter) mode?

**Electronic Front Curtain (EFCS)** mode is a flexible hybrid exposure mode available in many modern DSLRs and mirrorless cameras (Nikon D850, Z6, Z7, Sony A7 III).

In this mode, the first (opening) mechanical curtain **does not move at all** - exposure of the frame begins electronically resetting a row of matrix pixels. The exhibition is completed by a physical second curtain.

The main advantages of the EFCS mode

1. Reduced mechanical wear by 50%:Since the first mechanical curtain is not cocked and descends, the resource of mechanical components is consumed twice as slow.
2. Complete elimination of Shutter Shock (Microsmear):No mechanical shock at the beginning exposure provides crystal clarity when shooting macro and long-focus lenses.
3. Quiet descent:Reduce noise levels when filming in theaters or ceremonies.

Hidden Side Effect: Cutting Bokeh Discs

When using EFCS at ultra-fast shutter speeds (faster than **1/2000 second**) with fast optics (f/1.2, f/1.4, f/1.8) there is a physical side effect:

Due to the difference in spatial distance between the sensor plane and the physical second curtain, blur disks bokehs are cut in half**, becoming like flattened ovals or “lemon slices”.

Shutter Mode Guidelines

Shooting script	Recommended mode	Reason for choice
Landscape, macro, studio (shutter speed 1/10 – 1/500)	EFCS (Electronic Front Curtain)	Zero micro-lubrication and saving curtains
Portraits at f/1.4 open in the sun (1/4000)	Pure mechanics (Mechanical)	Maintaining a perfect round bokeh shape
Sports, reporting, quiet shooting	Silent (Fully electronic)	Speed ​​and no wear