Sony a9 vs Sony a5100

This is a full comparison between the cameras Sony a9 and Sony a5100. We compare them by looking at the categories you see below.

Sony a9

Sony a5100

Manufacturing

These cameras are both manufactured by Sony.

Sony a9 were released 2017 and Sony a5100 was released 2014. That is a 3 years difference. In tech, this period can be of interest since technology is always improving, etc.

Camera	Released
Sony a9	2017
Sony a5100	2014

Type of camera

Both these cameras are Mirrorless cameras. No difference there.

Sensors / crop factor

These cameras have different sensors. Sony a9 has a "Sony Full Frame"-sensor while Sony a5100 has a "Sony APS-C"-sensor, and their difference in sensors will also affect the crop factor and experience focal length. See the table below.

Camera	Focal length, 50mm f/1.8 **
Sony a9	50 mm Full-frame sensor No crop factor/focal length multiplier
Sony a5100	75 mm Sony APS-C sensor Crop factor/focal length multiplier by * 1.5

** 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 a9 has a 24 MP (Megapixels) resolution while Sony a5100 has 24 MP. If we break down this in more detail this is the data behind the numbers:

Camera	Megapixels
Sony a9	24 MP 24000000 pixels 6000 x 4000
Sony a5100	24 MP 24000000 pixels 6000 x 4000

ISO range

Sony a9 has a larger ISO-range than Sony a5100. Sony a9 has an ISO range that stretches from 100 to 51200 while Sony a5100 has 100 to 25600.

Camera	ISO Range
Sony a9	100-51200
Sony a5100	100-25600

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 a9
Lens compatibility chart for Sony a5100

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Sony a9 can shoot up to 20 pictures per seconds and Sony a5100 can shoot up to 6 pictures per seconds.

Camera	FPS (Frames per second)
Sony a9	20
Sony a5100	6

Ability to record movies

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

In this case, both Sony a9 and Sony a5100 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 138% heavier than Sony a5100 and its 283 gr (or 0.62 lb).

Camera	Weight
Sony a9	673 gr 1.48 lb
Sony a5100	283 gr 0.62 lb