What is the aperture ?

22/02/2017

The F-stop

It is the little number written after the length of your lens. So for a prime lens (no zoom) 50mm 1.8, the aperture maximal is 1.8. Smaller the number is, more light is coming to hit the sensor. That is why many photographers talks about the speed of the lens. As more light comes in, the speed needed to have a certain amount of light diminushed. So a lens with 1.8 maximum aperture is faster than a lens with 4. As a 4 is faster than a 8.

The implication of a fast lens.

Why not only use fast lens then ? It is because faster the lense is (bigger the aperture is) smaller the size of the "in focus" area will be. That is why everything out of a little range is blurry. You will need to balance the speed of your lens and the range of the area you wish to be in focus. The longer the lens the more blur you will get for your out of focus area.