Canon EOS 400D vs Canon EOS 300D

This is a full comparison between the cameras Canon EOS 400D and Canon EOS 300D. We compare them by looking at the categories you see below.

Manufacturing

These cameras are both manufactured by Canon.

Type of camera

Both these cameras are DSLR cameras. No difference there.

Sensors / crop factor

Both these cameras have the same sorts of sensor (called "APSC") 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.

** 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 (Canon)

Resolution

Canon EOS 400D has a 10,1 MP (Megapixels) resolution while Canon EOS 300D has 6,3 MP. If we break down this in more detail this is the data behind the numbers:

Canon EOS 400D has a 60 % larger resolution than Canon EOS 300D. 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

Both of these cameras offer the exact same ISO range. They both have 100 to 1600.

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 Canon EOS 400D
Lens compatibility chart for Canon EOS 300D

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Canon EOS 400D can shoot up to 3 pictures per seconds and Canon EOS 300D can shoot up to 2,5 pictures per seconds.

Ability to record movies

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

Though, neither Canon EOS 400D or Canon EOS 300D can shoot movies so if that is a functionality that you are really looking for you should look elsewhere.

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 300D weighs 645 gr (equal to 1,42 lb) which is 16% heavier than Canon EOS 400D and its 556 gr (or 1,23 lb).