Nikon D5100 vs Canon EOS 20D Astrophotography

This is a full comparison between the cameras Nikon D5100 and Canon EOS 20D Astrophotography. We compare them by looking at the categories you see below.

Nikon D5100
Canon EOS 20D Astrophotography


Nikon D5100 is manufacturered by Nikon but Canon EOS 20D Astrophotography is from Canon. Both Nikon and Canon are well known brands though.

Nikon D5100 were released 2011 and Canon EOS 20D Astrophotography was released 2005. That is a 6 years difference. In tech, this period of time can be of interest since technology is always improving etc.

Camera Manufacturer Released
Nikon D5100 Nikon 2011
Canon EOS 20D Astrophotography Canon 2005

Type of camera

Both these cameras are DSLR cameras. No difference there.

Sensors / crop factor

These cameras have different sensors. Nikon D5100 has a "DX"-sensor while Canon EOS 20D Astrophotography has a "APSC"-sensor, and their difference in sensors will also effect the crop factor and experience focal length. See the table below.

Camera Experienced focal length when using a lens with 50mm focal length (ex a common "50mm f/1.8")
Nikon D5100 75 mm (a Nikon DX sensor have a crop factor / focal length multiplier by * 1.5)
Canon EOS 20D Astrophotography 80 mm (a Canon APS-C sensor have a crop factor / focal length multiplier by * 1.6)

Learn more about crop factor and focal length multiplier here:
Camera selection can affect the focal length (Nikon)
Camera selection can affect the focal length (Canon)


Nikon D5100 has a 16,2 MP (Megapixels) resolution while Canon EOS 20D Astrophotography has 8,2 MP. If we break down this in more detail this is the data behind the numbers:

Camera Megapixels Pixel (total) Pixels (width) Pixels (height)
Nikon D5100 16,2 MP 16084992 4928 3264
Canon EOS 20D Astrophotography 8,2 MP 8185344 3504 2336

Nikon D5100 has a 97 % larger resolution than Canon EOS 20D Astrophotography. This could give you more details in the picture but also a possibility to crop more in the pictures, afterwards while editing the pictures, if needed that is.

ISO range

Nikon D5100 has a larger ISO-range than Canon EOS 20D Astrophotography. Nikon D5100 has an ISO range that stretches from 100 to 6400 while Canon EOS 20D Astrophotography has 100 to 3200.

Camera ISO Range
Nikon D5100 100-6400
Canon EOS 20D Astrophotography 100-3200

Autofocus and lens compatibility

There is a big diffence between these two cameras. Canon EOS 20D Astrophotography 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 that work with each camera:
Lens compatibility chart for Nikon D5100
Lens compatibility chart for Canon EOS 20D Astrophotography

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definately be of interest. Nikon D5100 can shoot up to 4 pictures per seconds and Canon EOS 20D Astrophotography can shoot up to 5 pictures per seconds.

Camera FPS (Frames per second)
Nikon D5100 4
Canon EOS 20D Astrophotography 5

Ability to record movies

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

When comparing these two cameras there is only one of them that can shoot movies and that is Nikon D5100. Unfortunately Canon EOS 20D Astrophotography does not support recording movies and movie clips.


The weight of the camera can be an extremely important factor, especially if the camera is about to be used, carried around, for several hours at the time.

Canon EOS 20D Astrophotography weighs 770 gr (equal to 1,7 lb) which is 26% heavier than Nikon D5100 and its 611 gr (or 1,35 lb).

Camera Weight (in gram) Weight (in pounds)
Nikon D5100 611 gr 1,35 lb
Canon EOS 20D Astrophotography 770 gr 1,7 lb