Sony E mount reverse engineer
Sony E mount reverse engineer
E-mount electronic protocol (full) spec is only available to companies under non-disclosure agreement and strict Sony requirements (which aren't disclosed too), so general public can only know only reverse engineered knowledge. This page contains data collected from public postings
http://www.dyxum.com/dforum/emount-electronic-protocol-reverse-engineering_topic119522.html
http://www.dpreview.com/forums/post/56133485 http://www.dpreview.com/forums/post/56587712 http://www.dpreviewer.net/forums/thread/3968755?page=2
E-mount protocol is UART-based, little Endian.
Pinout of the mount is as follows (These pins are from left to right looking at a lens from the rear):
1: LENS_GND - Lens motor GND
2: LENS_POWER - Lens motor power. Can be either 5.0v or unregulated Vbat (7.4v nominal) - This is somehow negotiated between body and lens
3: LOGIC_GND - Ground for lens logic circuitry
4: BODY_VD_LENS - As-of-yet unknown body->lens signalling. In nearly all cases, is normally high but pulses low at a very low duty cycle at 60 Hz (is it 50 in EU?)
5: LOGIC_VCC - Lens logic power. 3.15v All data lines described below are 3.15v logic high
6: LENS_CS_BODY - Handshaking line from lens to body. Always high when RXD is transferring data, normally low
7: RXD - Serial data from lens to body. Starts at 750 kbaud, usually negotiates up to 1.5 Mbaud during init. 8N1 lsb-first
8: TXD - Serial data from body to lens. Same speeds as above
9: BODY_CS_LENS - Handshaking line from body to lens. Always high when TXD is transferring data
10: LENS_XDETECT - (weakly) pulled high by the body. Grounded to LOGIC_GND by the lens, or sometimes via 680 ohm resistor (Viltrox EF-NEX II). Used to detect presence of a lens. Body will not output power unless this is grounded.
Lens ID [[1]]
The main focus position calculations (Packet 0x30 bytes 7/8 and bytes 25/26) appear to be reasonably correct/consistent with all native E-mount lenses I've looked at. These two values are always VERY close to each other and I don't know why there are two fields with almost the exact same data, but Techart seems to have gotten this one right. They are influenced by focal length but not in a linear fashion. They increase as the lens focuses closer (lens element moves away from sensor).
However, there's a third focus position field at bytes 31/32 The value of this field is approximately 110*sqrt(focal length) at infinity focus!
Some photos of mounts at the Apertus open source cinema wiki
Openmemories hack
On cameras having Sony playmemories, Openmemories allows to install any Android apps and remove 30 min video recording limit. Shared with some non-E photo cameras and action cameras. [2]
Multiport protocol/LANC
Wi-Fi protocol
Published. Common also to some non E-mount Sony cameras. Uses JSON. https://developer.sony.com/2013/11/29/how-to-develop-an-app-using-the-camera-remote-api-2/
Patents
Interchangeable lens and lens-data communication method US9392150 patent describes "advantages" of E-mount. [[4]] SLT adapter [5] Phase AF pixels in rows US20170223241 Same as E-mount but 2 pins less
https://github.com/LexOptical/E-Mount more details and partial implementation from Alexander Gee
