Last week we talked a little bit about Exposure, and how you can change it by adjusting both the Aperture (opening of the diaphragm) and Shutter Speed.
Today, we'll talk more about Aperture.
The aperture, will not only affect the amount of light entering but also determine the Depth Of Field, which "refers to the range of distance that appears acceptably sharp" on your image.
The wider the aperture the shallower the depth of field.
And inversely, the narrower your aperture, the longer the depth of field.
The aperture will be noted on your camera with the symbol (F), and is called F(stop).
A small F(stop), like for example F(1.2), or F(2) represents actually a wide opening, and consequently is chosen if you wish to have a small depth of field (for example for portraits).
A big F(stop), for example f(22), represents a small opening, and is chosen if you want to have a long depth of field (for landscape photography).
Here is an example of F(stop) you may see on your camera.
(Depending of your camera and lens you may have more or less F(Stop)s.
On (D)SLRs cameras you have two modes in which you will be able to change your Aperture:
- M - Manual
- Av (Canon) / A (Nikon) - Aperture Priority
In Manual Mode (M), you will have to chose both the aperture and the shutter speed to ensure the right exposure for your images. It takes a little bit of practice, so for today let's focus on Aperture Priority Mode, which is a great option to start practicing. In this mode, you are going to chose whatever aperture you want (depending of the depth of field you want on your image), and your camera will automatically match this aperture with a suitable shutter field to ensure a good exposure of your picture.
Ready to try?
Why don't you take 6 eggs (or any other object really :-)), and align them on a table.
Now set up your camera on Aperture Priority Mode (Av for Canon, or A for Nikon).
Take 4 different pictures, without moving your objects nor your camera, at 4 different F(stop)s.
I did also the exercise to show you.
In all 4 cases I focused on the egg number (1) (you will notice that the depth of field does not apply only to things behind your subject, but also in front).
In this first image, I chose an extremely wide Aperture (and therefore shallow Depth of Field). You can see that only Egg 1 is in focus.
Second image, without changing my focus, I moved up a little my F(stop), to F(4). Egg 2 is now also in focus.
Third image, without changing my focus, I moved up my F(stop) even more, to F(8). Egg 3 is now also in focus.
Fourth image, without changing my focus, I moved up my F(stop) to F(22). Egg 4 is now also in focus, as well as egg 0.
Your turn to give it a try! :-)
Feel free to use the Comments section to share your images of this exercise, but also to ask any question.
Next time.... Shutter Speed....