Alright, I will own up to it, the following text is a copied text from a google search, but I will explain it in my own words and how I understand it from the copied text, here we go!!
'Focus is a basic tenet of photography. It's typically given a definition in photobooks, but not fully explained. The standard definitions of focus is the position at which rays of light from a lens converge to form a clear and sharply defined image on a focal plane.'
So in my own understanding, I think that focus is when a ray of light is hit against the lens and the lens are made to try and in a way 'adapt' to the ray of light at the lens, for example, at night time you can take pictures but wont see much. Stars are a source of light and they do have light rays which go into the lens, as these light rays are so much weaker than the sun's light rays, we sort of have to imagine that the star's light ray is a much more gentle light ray, which means we have to adjust the settings to make sure the light is shown and that other things and objects can be seen too (if you are out in the wild).
'Focus is a basic tenet of photography. It's typically given a definition in photobooks, but not fully explained. The standard definitions of focus is the position at which rays of light from a lens converge to form a clear and sharply defined image on a focal plane.'
So in my own understanding, I think that focus is when a ray of light is hit against the lens and the lens are made to try and in a way 'adapt' to the ray of light at the lens, for example, at night time you can take pictures but wont see much. Stars are a source of light and they do have light rays which go into the lens, as these light rays are so much weaker than the sun's light rays, we sort of have to imagine that the star's light ray is a much more gentle light ray, which means we have to adjust the settings to make sure the light is shown and that other things and objects can be seen too (if you are out in the wild).
Here are some of my own examples of focus.