At our public observatory we acquired a Sony A7S (12MPix) camera just 4 weeks ago. I got myself a Sony A7II (24MPix) We are still in testing mode with KStars/Ekos with the observatory hardware so we didn't even try to control the A7xx using Ekos. But we did some testing using gphoto2.
So here is some information about what we found out and what seems to work for A7S and A7II. (Btw the A7II registers as "Sony ILCE-7M2" with gphoto!)
a) gphoto2 support for Sony improved with version 2.5.10 and the newest 2.5.11. Current gphoto version with Ekos is 2.5.9.
For Debian the 2.5.10. version has been compiled from source by a colleague of mine. Same version comes with SUSe Leap 42.2 which I use for testing.
b) Version 2.5.10 supports some settings (--set-config) such as
gphoto2 --set-config imagesize=0 # 0="big format"; 10=middle; 2=small
gphoto2 --set-config- iso=1600 # 50 to 25600 (A7II); 409600 (A7S)
or use
gphoto2 --set-config-index iso=19 # 19=3200; 0= auto-ISO; 7=200; 10=400; 13=800;
# 16=1600; 22=6400; 25=12800
gphoto2 --set-config focusmode=0 # 0=manuell; 1=automatisch; 2=AF->C; 3=AF-A
gphoto2 --set-config whitebalance=1 # 1= Tageslicht; 0=auto; 2=shadow; 3=Wolkig
gphoto2 --set-config exposurecompensation=0 # 0=0
# flashmode funktioniert nicht MH 11.12.2016
# gphoto2 --set-config-index flashmode=0 # 0= "flash off"
gphoto2 --set-config f-number=4.0 # f-number in steps of 0.1
gphoto2 --set-config imagequality=3 # 3=RAW; 0=Standard; 1=fein; 2=???; 4=RAW+JPEG
gphoto2 --set-config aspectratio=3:2 # "3:2 oder "16:9"
gphoto2 --set-config capturemode=0 # 0=single exp; 1= multiple?!; 2=continuous
# 3= selftimer 2s; 4=selftimer 10s
gphoto2 --set-config shutterspeed=100/10 # 10s; from 1/10 indicate in n/10th!
# max.: 300/10 (=30s)
# bulb can be set manually at camera only!)!
c) short exposure (up to 30 s), for example 10 s:
set camera to manual (program wheel), then
gphoto2 --set-config shutterspeed=100/10
gphoto2 --capture-image-and-download --filename xxx.jpg
d) exposure times beyond 30 s
set camera to manual (program wheel) and manually set exposure time to "bulb" first, then
gphoto2 --set-config bulb=1 --wait-event=120s --set-config bulb=0 # exposure time 120s
(I have no idea why bulb=1/0 is needed; "gphoto2 --set-config bulb=1" for itself returns an error?!)
We succeeded controlling the A7xx with simple bash scripts (setting the config values and starting a do loop) such as taking 40 pictures with 30s exposure, or 20 pictures with 90s exposure using a separate laptop for camera control.
I guess more recent versions of gphoto2 are required for better control, but don't expect to much from gphoto since from what I read in other forums Sony is not a vivid supporter of open software control. (For example I doubt there ever will be a preview other than by the HDMI camera port;
so I suppose there is no chance for auto focusing. Edit: This of course was incorrect, since focusing works on downloaded images, not on some kind of preview. USB-based preview probably will never be supported by Sony.