Focal length
Using a focal length, you can also affect our important parameter in the shooting depth of sharpness. Here it is necessary to remember such a moment that the flu will be less as much as the distance will be less to the lens. And quite the opposite, there will be more flu, as much as the object will be before your lens. Everything is extremely simple, you only need to understand how this principle works. You can combine the desired diaphragm using the desired focal length, thus obtaining the depth of sharpness you need.
