Mirrorless specifics: Mysteries of the Sony Alpha family

In the workshop, owners of Sony A7 III and A7R IV often ask with concern: * “Master, my report says 120 000 triggers, but I shot half of the video clips and half with an electronic shutter! The matrix is worn out or shutter?"*.

Let's look at how shooting recording works in Sony cameras.

Feature of EFCS (Electronic Front Curtain Shutter) mode

Most Sony mirrorless cameras have **Electronic Front Curtain Curtain (EFCS)** enabled by default. When photographed by a mechanic opens in advance, the exhibition starts with an electronic reset of the matrix, and closes with a physical mechanic.

• In `EFCS` mode the curtain makes only **1 movement** per frame instead of **2 movements** in fully mechanical mode.
• The wear of the mechanical unit when EFCS is turned on is reduced by exactly 2 times!

Difficulty reading tags in ARW files

Sony cameras compress their RAW files (.ARW). Depending on the firmware version, the shutter tag was moved from one branch EXIF to another (`Sony Tag 0x9050` or `Sony ImageCount`). The old A6000 and the first A7 have normal sites show either an error or incorrect data.

Table of Sony shooting modes and physical wear

Sony Shutter Mode	Curtain movements	Wear of mechanics in 1 frame
Fully Mechanical	2 cycles (Opening + Closing)	100% normal wear
EFCS (Electronic Front Curtain)	1 cycle (Closing only)	50% wear (resource saving)
Silent Shutter	0 cycles (Sensor reading only)	0% mechanical wear