Sony a57 vs Sony a55

This is a full comparison between the cameras Sony a57 and Sony a55. We compare them by looking at the categories you see below.

Sony a57

Sony a55

Manufacturing

These cameras are both manufactured by Sony.

Sony a57 were released 2012 and Sony a55 was released 2010. That is a 2 years difference. In tech, this period can be of interest since technology is always improving, etc.

Camera	Released
Sony a57	2012
Sony a55	2010

Type of camera

Sensors / crop factor

Both these cameras have the same sorts of sensor (called "Sony APS-C") which means that if you compare these cameras side by side the lenses will also have the same experienced focal length. Neither of the cameras has a Full frame sensor which means that you will get a "crop factor" where the camera's sensor size affect the focal length with a multiplier.

Camera	Focal length, 50mm f/1.8 **
Sony a57	75 mm Sony APS-C sensor Crop factor/focal length multiplier by * 1.5
Sony a55	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 a57 has a 16 MP (Megapixels) resolution while Sony a55 has 16 MP. If we break down this in more detail this is the data behind the numbers:

Camera	Megapixels
Sony a57	16 MP 16032768 pixels 4912 x 3264
Sony a55	16 MP 16032768 pixels 4912 x 3264

ISO range

Sony a57 has a larger ISO-range than Sony a55. Sony a57 has an ISO range that stretches from 100 to 16000 while Sony a55 has 100 to 12800.

Camera	ISO Range
Sony a57	100-16000
Sony a55	100-12800

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 a57
Lens compatibility chart for Sony a55

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Sony a57 can shoot up to 12 pictures per seconds and Sony a55 can shoot up to 10 pictures per seconds.

Camera	FPS (Frames per second)
Sony a57	12
Sony a55	10

Ability to record movies

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

In this case, both Sony a57 and Sony a55 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 a57 weighs 618 gr (equal to 1.36 lb) which is 24% heavier than Sony a55 and its 500 gr (or 1.1 lb).

Camera	Weight
Sony a57	618 gr 1.36 lb
Sony a55	500 gr 1.1 lb