Canon EOS 4000D Instruction Manual page 144

Menu Function Settings
Aspect ratioN

The image's aspect ratio can be set to [3:2], [4:3], [16:9], or [1:1].
The area surrounding the image area is masked in black when the
following aspect ratios are set: [4:3] [16:9] [1:1].
JPEG images will be saved with the set aspect ratio. RAW images
will always be saved with the [3:2] aspect ratio. The selected aspect
ratio information is added to the RAW image file. When you process
the RAW image with the EOS software, this allows you to generate
an image with the same aspect ratio that was set for shooting. In the
case of the [4:3], [16:9], and [1:1] aspect ratios, the lines to indicate
the aspect ratio will appear during image playback, but they are not
actually drawn on the image.
Image
Quality
3:2
5184x3456
3
(17.9 megapixels)
3456x2304
4
(8.0 megapixels)
2592x1728
a
(4.5 megapixels)
1920x1280
b
(2.5 megapixels)
720x480
c
(350,000 pixels)
The asterisked image-recording quality settings do not match the

respective aspect ratio exactly.
The image area displayed for the asterisked aspect ratio may be slightly

different from the actual image area. Check the captured images on the
LCD monitor when shooting.
If you use a different camera to directly print images shot with this

camera in the 1:1 aspect ratio, the images may not be correctly printed.
144
Aspect Ratio and Pixel Count (Approx.)
4:3
4608x3456
(16.0 megapixels)
3072x2304
(7.0 megapixels)
2304x1728
(4.0 megapixels)
1696x1280*
(2.2 megapixels)
640x480
(310,000 pixels)
16:9
5184x2912*
(15.1 megapixels)
3456x1944
(6.7 megapixels)
2592x1456*
(3.8 megapixels)
1920x1080
(2.1 megapixels)
720x400*
(290,000 pixels)
1:1
3456x3456
(11.9 megapixels)
2304x2304
(5.3 megapixels)
1728x1728
(3.0 megapixels)
1280x1280
(1.6 megapixels)
480x480
(230,000 pixels)