The aspect ratio is the relationship between an image's height and width. Aspect ratios are more often written with the width first, followed by the height. The aspect ratio you use depends on the type of project you're shooting. It is usually recommend to use 4:3 for photos and 16:9 for videos.
A 3:2 aspect ratio is used by 35mm crop-sensor and full-frame DSLRsA digital single-lens reflex camera (digital SLR or DSLR) is a digital camera that combines the optics and the mechanisms of a single-lens reflex (SLR) camera with a digital imaging sensor. The reflex design scheme is the primary difference between a DSLR and other digital cameras. In the reflex design, light travels through the lens and then to a mirror that alternates to send the image to either the viewfinder or the image sensor. The viewfinder of a DSLR presents an image that will not differ substantially from what is captured by the camera's sensor but presents it as a direct optical view through the lens, rather than being captured by the camera's image sensor and displayed by a digital screen. DSLR is often (wrongly) used to describe cameras that are Micro Four Thirds or Bridge Camera - just because they look similar. This can bee seen when cameras are offered for sale. More, some Leica medium format cameras, most mirrorlessTechnically speaking most DSLR, point-and-shoot and smartphone cameras are mirrorless, in that they don’t have internal mirrors. However, mirrorless camera is a specific term for a camera where the sensor is directly exposed to light and the photographer has a preview of the potential image at all times to view on an electronic viewfinder. For example the Olympus and Panasonic micro four-thirds cameras are mirrorless. More cameras, high-end compact cameras, and most 35mm film cameras.
The 4:3 aspect ratio is used by Micro Four Thirds cameras, many compact cameras, some medium format digital cameras, as well as medium format film cameras using the 6 cm x 4.5 cm format.
