The sharpness of the image, a range of distances from the camera will be acceptably sharp.
One of the most important tools of a photographer is focus. It holds all the emotional impact of an image and the power to build a photo's story. This huge impact on photography means photographers need to have a solid grasp on how to use it. There are two kinds of focus as we can see; deep focus and shallow focus.
Deep focus is a photographic and cinematographic technique that keeps the depth of field wide enough to include objects in front of and behind the scene. Thus, there is no out-of-focus space in the deeply arranged scene and the image consists of foreground, middle and background presented equally to the audience. In short, thanks to the deep focus technique, the depth of the image can be evaluated better.
On the other hand, in the shallow focus technique, the players in the dialogue or the objects to be emphasized are kept as close to each other as possible, leaving other players and objects in the background blurred.
In cinema, Orson Welles and cinematographer Gregg Toland are seen as the best-known representatives of the deep focus technique. Especially the movie "Citizen Kane" (1941), a work of these two, is a real textbook for the use of this technique.
Shallow focus is a photographic and cinematographic technique that narrows the depth of sharpness. Unlike the deep focus technique, with this technique, only a single part of the image is kept in focus; the rest of the image is outside this point, i.e. it is shown blurry.
With shallow focus, directors and photographers emphasize where the viewer should pay particular attention, by making one part of the picture more prominent than other parts.
Focus can have a huge impact on your photography. Learning how to use it can draw attention to your subject, increasing visual interest in your images. To take advantage of this technique, photographers need to know the basics of focus and depth of field.