Sony a7 III vs Sony a9

This is a full comparison between the cameras Sony a7 III and Sony a9. We compare them by looking at the categories you see below.

Manufacturing

These cameras are both manufactured by Sony.

Sony a7 III were released 2018 and Sony a9 was released 2017. That is a 1 years difference. In tech, this period can be of interest since technology is always improving, etc.

Camera Released
Sony a7 III 2018
Sony a9 2017

Type of camera

Both these cameras are Mirrorless cameras. No difference there.

Sensors / crop factor

Both these cameras have the same sorts of sensor (called "Sony Full Frame") which means that if you compare these cameras side by side the lenses will also have the same experienced focal length. Since both cameras have a Full frame sensor there will be no crop factor.

Camera Focal length, 50mm f/1.8 **
Sony a7 III 50 mm
Full-frame sensor
No crop factor/focal length multiplier
Sony a9 50 mm
Full-frame sensor
No crop factor/focal length multiplier

** Experienced focal length when using a lens such as a common "50mm f/1.8"

Learn more about crop factor and focal length multiplier here:
Camera selection can affect the focal length (Sony)

Resolution

Both these cameras have the exact same resolution. Sony a7 III has a 24 MP (Megapixels) resolution while Sony a9 has 24 MP. If we break down this in more detail this is the data behind the numbers:

Camera Megapixels
Sony a7 III 24 MP
24000000 pixels
6000 x 4000
Sony a9 24 MP
24000000 pixels
6000 x 4000

ISO range

Both of these cameras offer the exact same ISO range. They both have 100 to 51200.

Camera ISO Range
Sony a7 III 100-51200
Sony a9 100-51200

Autofocus and lens compatibility

Both of these cameras have a built-in autofocus motor. Some lenses, that support autofocus, do not have an autofocus motor of their own but this won't cause any problems with these two cameras.

Here is a complete overview of which lenses work with each camera:
Lens compatibility chart for Sony a7 III
Lens compatibility chart for Sony a9

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Sony a7 III can shoot up to 10 pictures per seconds and Sony a9 can shoot up to 20 pictures per seconds.

Camera FPS (Frames per second)
Sony a7 III 10
Sony a9 20

Ability to record movies

It is becoming more and more popular to record movies with digital cameras.

In this case, both Sony a7 III and Sony a9 can shoot movies.

Weight

The weight of the camera can be an extremely important factor, especially if the camera is about to be used, or carried around, for several hours at a time.

Sony a9 weighs 673 gr (equal to 1.48 lb) which is 4% heavier than Sony a7 III and its 650 gr (or 1.43 lb).

Camera Weight
Sony a7 III 650 gr
1.43 lb
Sony a9 673 gr
1.48 lb

Sony a7 III vs Sony a9 Specs

Below you will find the complete and detailed technical specs for both Sony a7 III and Sony a9, next to each other. Each category of data is a link to an article covering the subject, giving you a deeper understanding so you can better understand the strengths and weaknesses of the two camera models.

Product
Sony a7 III
Sony a9
Name Sony a7 III Sony a9
Manufacturer Sony Sony
Release Date and Price
Sony a7 III
Sony a9
Release Year 2018 2017
Release Date 2018-02-27 2017-04-19
MSRP 1999 USD 4499 USD
Buy it today
Camera Type
Sony a7 III
Sony a9
Camera Type Mirrorless Mirrorless
Sensor
Sony a7 III
Sony a9
Sensor Size Full Frame (approx 36 x 24 mm) Full Frame (approx 36 x 24 mm)
Sensor Type BSI-CMOS Stacked CMOS
Resolution 6000 x 4000 pixels 6000 x 4000 pixels
Megapixels 24 MP 24 MP
Image Processor Bionz X Bionz X
Image
Sony a7 III
Sony a9
ISO Range 100 - 51200 100 - 51200
White Balance Presets 11 10
Custom White Balance Yes Yes
Image Stabilization Yes
(Sensor-Shift)
Yes
(Sensor-Shift (5-axis))
Image Stabilization CIPA Rating 5 stops 0 stops
Uncompressed format RAW RAW
Optics & Focus
Sony a7 III
Sony a9
Autofocus Motor Yes Yes
Autofocus Contract Detect (sensor)
Phase Detect
Multi Area
Center
Selective Single Point
Tracking
Single
Continuous
Touch
Face Detection
LiveView
Contract Detect (sensor)
Phase Detect
Multi Area
Center
Selective Single Point
Tracking
Single
Continuous
Touch
Face Detection
LiveView
Focus Points 693 693
Lens Mount Sony E

See Compatible Lenses
Sony E

See Compatible Lenses
Focal Length Multiplier Full frame
No multiplier
Example:
24 mm remains 24 mm
50 mm remains 50 mm
100 mm remains 100 mm
200 mm remains 200 mm
Full frame
No multiplier
Example:
24 mm remains 24 mm
50 mm remains 50 mm
100 mm remains 100 mm
200 mm remains 200 mm
Screen & Viewfinder
Sony a7 III
Sony a9
Articulated LCD Tilting Tilting
Screen size 3” 3”
Screen dots 921600 1440000
Touch screen Yes Yes
Screen type N/A TFT LCD
Live view Yes Yes
Viewfinder Type Electronic Electronic
Viewfinder Coverage 100% 100%
Viewfinder Magnification 0.78x 0.78x
Viewfinder Resolution 2359296 3686400
Photography features
Sony a7 III
Sony a9
Frames per second 10 fps 20 fps
Minimum Shutter Speed 30 seconds 30 seconds
Maximum Shutter Speed 1/8000 seconds 1/8000 seconds
Built-in Flash No No
Built-in Flash Range N/A N/A
External Flash Yes Yes
Self-Timer Yes Yes
Time-lapse No No
Metering modes Multi
Center Weighted
Highlight Weighted
Spot
Average
Multi
Center Weighted
Highlight Weighted
Spot
Average
Exposure Compensation +/- 5 (at 1/3 EV, 1/2 EV steps) +/- 5 (at 1/3 EV, 1/2 EV steps)
Videography features
Sony a7 III
Sony a9
Video recording Yes Yes
Video format MPEG4
H.264
XAVC-S
AVCHD
MPEG4
H.264
AVCHD
Video resolution 1920 x 1080
3840 x 2160
1280 x 720
1920 x 1080
3840 x 2160
Built-in Microphone Yes Yes
Built-in Speakers Yes Yes
Storage
Sony a7 III
Sony a9
Memory Card Memory Stick Pro Duo
SD/SDHC
SD/SDHC
Connectivity
Sony a7 III
Sony a9
HDMI Output Yes Yes
Microphone Port Yes Yes
Headphone Port Yes Yes
Wireless Yes
Built-in (with NFC and wireless control via PlayMemories Mobile app)
Yes
Built-in (802.11/b/g/n with NFC)
Remote Control Wired Yes (Wired or wireless)
GPS No No
Body & Dimensions
Sony a7 III
Sony a9
Enviromentally sealed Yes Yes
Battery Battery Pack Battery Pack
Battery Details NP-FZ100 lithium-ion battery and charger
NP-FZ100
Battery Life (CIPA) 710 shots 650 shots
Width 127 mm 127 mm
Height 96 mm 96 mm
Depth 74 mm 63 mm
Weight 650 gram 673 gram