Sony a9 II vs Nikon D5100

This is a full comparison between the cameras Sony a9 II and Nikon D5100. We compare them by looking at the categories you see below.

Sony a9 II

Nikon D5100

Manufacturing

Sony a9 II is manufacturered by Sony but Nikon D5100 is from Nikon. Both Sony and Nikon are well known brands though.

Sony a9 II were released 2019 and Nikon D5100 was released 2011. That is a 8 years difference. In tech, this period can be of interest since technology is always improving, etc.

Camera	Released
Sony a9 II	2019
Nikon D5100	2011

Type of camera

Sony a9 II is a Mirrorless camera while Nikon D5100 is a DSLR camera. More information about their differences will come soon.

Sensors / crop factor

These cameras have different sensors. Sony a9 II has a "Sony Full Frame"-sensor while Nikon D5100 has a "Nikon DX"-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 II	50 mm Full-frame sensor No crop factor/focal length multiplier
Nikon D5100	75 mm Nikon DX 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)
Camera selection can affect the focal length (Nikon)

Resolution

Sony a9 II has a 24 MP (Megapixels) resolution while Nikon D5100 has 16,2 MP. If we break down this in more detail this is the data behind the numbers:

Camera	Megapixels
Sony a9 II	24 MP 24000000 pixels 6000 x 4000
Nikon D5100	16,2 MP 16084992 pixels 4928 x 3264

Sony a9 II has a 49 % larger resolution than Nikon D5100. 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 a9 II has a larger ISO-range than Nikon D5100. Sony a9 II has an ISO range that stretches from 100 to 51200 while Nikon D5100 has 100 to 6400.

Camera	ISO Range
Sony a9 II	100-51200
Nikon D5100	100-6400

Autofocus and lens compatibility

There is a big difference between these two cameras. Sony a9 II has a built-in autofocus motor but Nikon D5100 does not. If you want to be able to use autofocus on Nikon D5100 there is a need for having an autofocus motor inside the lens. We really encourage you to look closely at our lens compatibility charts at the links below.

Here is a complete overview of which lenses work with each camera:
Lens compatibility chart for Sony a9 II
Lens compatibility chart for Nikon D5100

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Sony a9 II can shoot up to 20 pictures per seconds and Nikon D5100 can shoot up to 4 pictures per seconds.

Camera	FPS (Frames per second)
Sony a9 II	20
Nikon D5100	4

Ability to record movies

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

In this case, both Sony a9 II and Nikon D5100 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 II weighs 678 gr (equal to 1.49 lb) which is 11% heavier than Nikon D5100 and its 611 gr (or 1.35 lb).

Camera	Weight
Sony a9 II	678 gr 1.49 lb
Nikon D5100	611 gr 1.35 lb