Focus is a combination of lens aperture and light. Photo by: ‘Unsplash’. Smaller apertures, such as f/8 to f/16, will “force” all the light coming from outside to pass through a tiny hole and concentrate on the image sensor. As a result, a bigger part of the image will be in focus. On the other hand, wider apertures, such as f/1.4 to f/4, will spread all the light rays on a bigger part of the image sensor. Since the hole that I mentioned a few lines above will now be much bigger, you’ll end up with an image that has a smaller “depth of field” (we’ll talk more about this later).Practically speaking, you can check whether a picture is in focus or not by its sharpness. The sharper that it looks, the more it will be in focus. Be careful though, as sometimes photographers choose to highlight or hide some parts of the image through the use of focus. As such, it may be normal to see some out of focus areas as they visually enhance more of the sharp parts. I guess that’s what we call “the artistic side of photography”!
