Sony a77 vs Nikon D3100

This is a full comparison between the cameras Sony a77 and Nikon D3100. We compare them by looking at the categories you see below.

Sony a77

Nikon D3100

Manufacturing

Sony a77 is manufacturered by Sony but Nikon D3100 is from Nikon. Both Sony and Nikon are well known brands though.

Sony a77 were released 2011 and Nikon D3100 was released 2010. That is a 1 years difference. In tech, this period can be of interest since technology is always improving, etc.

Camera	Released
Sony a77	2011
Nikon D3100	2010

Type of camera

Sensors / crop factor

These cameras have different sensors. Sony a77 has a "Sony APS-C"-sensor while Nikon D3100 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 a77	75 mm Sony APS-C sensor Crop factor/focal length multiplier by * 1.5
Nikon D3100	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 a77 has a 24 MP (Megapixels) resolution while Nikon D3100 has 14,2 MP. If we break down this in more detail this is the data behind the numbers:

Camera	Megapixels
Sony a77	24 MP 24000000 pixels 6000 x 4000
Nikon D3100	14,2 MP 14155776 pixels 4608 x 3072

Sony a77 has a 70 % larger resolution than Nikon D3100. 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 a77 has a larger ISO-range than Nikon D3100. Sony a77 has an ISO range that stretches from 100 to 16000 while Nikon D3100 has 100 to 12800.

Camera	ISO Range
Sony a77	100-16000
Nikon D3100	100-12800

Autofocus and lens compatibility

There is a big difference between these two cameras. Sony a77 has a built-in autofocus motor but Nikon D3100 does not. If you want to be able to use autofocus on Nikon D3100 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 a77
Lens compatibility chart for Nikon D3100

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Sony a77 can shoot up to 12 pictures per seconds and Nikon D3100 can shoot up to 3 pictures per seconds.

Camera	FPS (Frames per second)
Sony a77	12
Nikon D3100	3

Ability to record movies

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

In this case, both Sony a77 and Nikon D3100 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 a77 weighs 732 gr (equal to 1.61 lb) which is 45% heavier than Nikon D3100 and its 505 gr (or 1.11 lb).

Camera	Weight
Sony a77	732 gr 1.61 lb
Nikon D3100	505 gr 1.11 lb