Sony a7S III vs Canon EOS 20D Astrophotography

This is a full comparison between the cameras Sony a7S III and Canon EOS 20D Astrophotography. We compare them by looking at the categories you see below.

Manufacturing

Sony a7S III is manufacturered by Sony but Canon EOS 20D Astrophotography is from Canon. Both Sony and Canon are well known brands though.

Type of camera

Sony a7S III is a Mirrorless camera while Canon EOS 20D Astrophotography is a DSLR camera. More information about their differences will come soon.

Sensors / crop factor

These cameras have different sensors. Sony a7S III has a "Sony Full Frame"-sensor while Canon EOS 20D Astrophotography has a "Canon APS-C"-sensor, and their difference in sensors will also affect the crop factor and experience focal length. See the table below.

** 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)
Camera selection can affect the focal length (Canon)

Resolution

Sony a7S III has a 12 MP (Megapixels) resolution while Canon EOS 20D Astrophotography has 8,2 MP. If we break down this in more detail this is the data behind the numbers:

Sony a7S III has a 47 % larger resolution than Canon EOS 20D Astrophotography. This could give you more details in the picture but also a possibility to crop more in the pictures, afterward while editing the pictures, if needed that is.

ISO range

Sony a7S III has a larger ISO-range than Canon EOS 20D Astrophotography. Sony a7S III has an ISO range that stretches from 80 to 102400 while Canon EOS 20D Astrophotography has 100 to 3200.

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 a7S III
Lens compatibility chart for Canon EOS 20D Astrophotography

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Sony a7S III can shoot up to 10 pictures per seconds and Canon EOS 20D Astrophotography can shoot up to 5 pictures per seconds.

Ability to record movies

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

When comparing these two cameras there is only one of them that can shoot movies and that is Sony a7S III. Unfortunately Canon EOS 20D Astrophotography does not support recording movies and movie clips.

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.

Canon EOS 20D Astrophotography weighs 770 gr (equal to 1.7 lb) which is 10% heavier than Sony a7S III and its 699 gr (or 1.54 lb).

Sony a7S III vs Canon EOS 20D Astrophotography Specs

Below you will find the complete and detailed technical specs for both Sony a7S III and Canon EOS 20D Astrophotography, 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 a7S III	Canon EOS 20D Astrophotography
Name	Sony a7S III	Canon EOS 20D Astrophotography
Manufacturer	Sony	Canon
Release Date and Price	Sony a7S III	Canon EOS 20D Astrophotography
Release Year	2020	2005
Release Date	2020-07-28	2005-06-01
MSRP	3499 USD	1499 USD
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Camera Type	Sony a7S III	Canon EOS 20D Astrophotography
Camera Type	Mirrorless	DSLR
Sensor	Sony a7S III	Canon EOS 20D Astrophotography
Sensor Size	Full Frame (approx 36 x 24 mm)	APS-C (approx 22.3 x 14.9 mm)
Sensor Type	BSI-CMOS	CMOS
Resolution	4240 x 2832 pixels	3504 x 2336 pixels
Megapixels	12 MP	8,2 MP
Image Processor	Bionz XR	DIGIC 2
Image	Sony a7S III	Canon EOS 20D Astrophotography
ISO Range	80 - 102400	100 - 3200
White Balance Presets	7	6
Custom White Balance	Yes	Yes
Image Stabilization	Yes (Sensor-Shift (5-axis))	No
Image Stabilization CIPA Rating	5.5 stops	0 stops
Uncompressed format	RAW	RAW
Optics & Focus	Sony a7S III	Canon EOS 20D Astrophotography
Autofocus Motor	Yes	Yes
Autofocus	Contract Detect (sensor) Phase Detect Multi Area Center Selective Single Point Tracking Single Continuous Touch Face Detection LiveView	Phase Detect Multi Area Selective Single Point Single Continuous
Focus Points	759	9
Lens Mount	Sony E See Compatible Lenses	Canon EF Canon EF-S 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	APS-C Sensor 1.6x multiplier Example: 24 mm becomes 38 mm 50 mm becomes 80 mm 100 mm becomes 160 mm 200 mm becomes 320 mm
Screen & Viewfinder	Sony a7S III	Canon EOS 20D Astrophotography
Articulated LCD	Fully articulated	Fixed
Screen size	3”	1.8”
Screen dots	1440000	118000
Touch screen	Yes	No
Screen type	TFT LCD	N/A
Live view	Yes	No
Viewfinder Type	Electronic	Optical (pentaprism)
Viewfinder Coverage	100%	95%
Viewfinder Magnification	0.91x	0.9× (0.56× 35mm equiv.)
Viewfinder Resolution	9440000	N/A
Photography features	Sony a7S III	Canon EOS 20D Astrophotography
Frames per second	10 fps	5 fps
Minimum Shutter Speed	30 seconds	30 seconds
Maximum Shutter Speed	1/8000 seconds	1/8000 seconds
Built-in Flash	No	Yes
Built-in Flash Range	N/A	12 meters
External Flash	Yes	Yes
Self-Timer	Yes	Yes
Time-lapse	No	Yes
Metering modes	Multi Center Weighted Highlight Weighted Spot Average	Multi Center Weighted Partial
Exposure Compensation	+/- 5 (at 1/3 EV, 1/2 EV steps)	+/- 2 (at 1/3 EV, 1/2 EV steps)
Videography features	Sony a7S III	Canon EOS 20D Astrophotography
Video recording	Yes	No
Video format	MPEG4 H.264 H.265 XAVC-S XAVC-HS	N/A
Video resolution	1920 x 1080 3840 x 2160	N/A
Built-in Microphone	Yes	No
Built-in Speakers	Yes	No
Storage	Sony a7S III	Canon EOS 20D Astrophotography
Memory Card	Compact Flash Express SD/SDHC	Compact Flash
Connectivity	Sony a7S III	Canon EOS 20D Astrophotography
HDMI Output	Yes	No
Microphone Port	Yes	No
Headphone Port	Yes	No
Wireless	Yes Built-in (802.11ac (dual band) + Bluetooth)	No
Remote Control	Yes (wireless or smartphone)	Yes (N3 connector)
GPS	No	No
Body & Dimensions	Sony a7S III	Canon EOS 20D Astrophotography
Enviromentally sealed	Yes	No
Battery	Battery Pack	Battery Pack
Battery Details	NP-FZ100 lithium-ion battery charger	Battery Pack BP-511A
Battery Life (CIPA)	600 shots	1000 shots
Width	129 mm	144 mm
Height	97 mm	106 mm
Depth	81 mm	72 mm
Weight	699 gram	770 gram