DoF ? What is that ?
Well some of you know I am sure. Most of you probably. But surely a few would be delighted to learn a little more about DoF.
It is an acronym for Depth of Field.
On a photograph like the one above, some parts are sharp, some are not in focus. The DoF is the distance between the nearest and the farthest object that appear sharp.
It is linked to several factors which it is best to know and to handle fluently. Otherwise you could end up getting a photograph not quite as you wanted it.
On a given camera, the DoF is in direct connection with the focal length of the lens and the aperture. Let us just say that the longer the focal length, the wider the aperture, the smaller the depth of field.
The photograph above with a much narrower aperture would have been more in focus. The same photograph shot with a wide angle would have been much more in focus. Here it was shot with a 135mm (telephoto lens) and at f/ 2.8 which is quite open.
Narrow DoF is used to emphasize a part of the image. On the contrary, deep DoF is prefered when all parts of the image have the same importance.
Here are two photographs with the same camera and same lens but very different apertures : f/ 22 and f/4
The result is very different.