Creatively Controlled Photography (part one)
There are two controls you need to master for creative control.
The first is aperture, we will start there.
Aperture controls range of focus. Higher numbers on the aperture increase that range of focus, while lower numbers decrease that range of focus.
You may have seen pictures, a portrait perhaps where the main subject is in crystal focus, but the background is a soft blur. The photographer did that on purpose, by choosing a lower aperture number.
Or perhaps you have seen a landscape picture where every object in the frame is crystal sharp in focus, from your feet to horizon. The photographer did that on purpose, by choosing a higher aperture number.
The aperture numbers start at 1, as the lowest possible aperture and then range up to about 32 as the highest. Though some lenses have apertures up to 45 or 64 or even 128 and higher.
Your lens is likely to go up to 22, or 32 tops.
You will rarely use or need to use any aperture higher than 32, so you are not missing anything really important for now.
You will probly have a lens with a lowest number of more than 2, and some lenses only go down to 4 or 5.6, and again, you are not really missing anything important by not having a lower aperture number for now.
Note that the lens can be focused at some distance, say 5 feet, and whatever is 5 feet from the camera will be in focus. The range of focus you control with aperture does not change the focus at that distance, the range of focus controlled by the aperture defines the focus of stuff that is NOT at 5 feet.
If you focus on a chess piece at 5 feet from the camera, it will be in focus and remain in focus no matter what aperture number you choose. If there is a vase of flowers that is 7 feet from the camera, and your cat is sleeping at 4 feet, then using the aperture, you can choose whether the flowers and cat are also in focus, or if they are blurry, and in some cases you can decide how blurry they look in the picture.
By using a higher number for aperture, you can have the vase and cat sharply focused as well as the chess piece, and by using a lower aperture number you can reduce the range of focus so that the cat and flowers are both blurry, and by choosing the lowest number of aperture, you can make them both as blurry as that lens will allow at those distances.
I mentioned distance at the end of that last sentence, because the distance from camera to focused subject also determines the range of focus.
As the focused distance gets smaller, the range of focus gets smaller. At very small distances, under one foot, for instance, the range of focus gets ridiculously small, sometimes less than an inch. An extreme closeup of a friend, where you focus on the tip of their nose, it may not be possible, even with the highest aperture number your lens has, to also get a good focus on their eye.
On the other end, as the distance to focused subject gets larger, the range of focus increases also, and that range of focus can be ridiculously large, for instance, if you focused on a tree at 200 feet, even with your smallest aperture number you would still see the horizon in very good focus, and the rose bush at 50 feet would also be in good focus. At large distances the range of focus becomes very very very large, in some cases out to infinity large.
For effective control over the range of focus, when you want to create focus blur, you should use a low aperture number at a shorter focus distance.
If you want crystal clear focus on as much of the depth of the scene as possible, then you should use a higher aperture number and a longer focus distance.
There is a complication with all this control of focus with the aperture.
Because the aperture also controls exposure.
If the aperture number goes down, then the shutter speed number must go up, to maintain correct exposure.
If the aperture number goes up, then the shutter speed number must go down.
Camera manufacturers build the settings with clicks, or stops, and they have engineered those stops so that each click has exactly the same effect on the exposure.
For instance, if the correct exposure is aperture number 8 and the shutter number set to 250, then changing 8 to 11, or 250 to 500, would each decrease the exposure by the exact same amount.
That means if you changed the 8 one click higher to 11, to keep the exposure correct, you need to use one click smaller shutter number, from 250, to 125.
You don’t really have to worry about what the numbers are, because all of them are exactly one click apart, so if you choose 2 clicks up on one, all you need to do is set the other one 2 clicks down. And vice versa.
How can you tell what the correct exposure is? Your camera most probably will tell you, or you can use an external exposure meter.
Using either one, you point the camera at the scene and read the numbers. Let’s imagine your camera tells you to use aperture 5.6 and a shutter of 250.
Good you know what the correct exposure is now. (that was much easier than you expected, huh?)
You can now forget about the camera settings, and look at the scene you are taking a picture of.
Is it a portrait style scene, with a sharp focused main subject with background and foreground objects out of focus?
Or perhaps a scene that begs for a crystal focus from front to back?
Maybe you should try BOTH to see which one works best for you?
In any case, you now know what to do, you can use a lower aperture number to get a small range of focus, and then change the shutter number up that same number of clicks or you could move closer to the subject, and leave both shutter and aperture alone.
You can get a larger range of focus by choosing a higher aperture number and then setting the shutter to a lower number the same number of stops to maintain the correct exposure.
Or, you could keep the numbers by moving to a further distance from the subject.
The important topic here is that you can control the range of focus in your picture, by choosing the aperture number and the distance to the subject. Once you have chosen an aperture, then the shutter must be set correctly to get correct exposure, but you know how to do that now also, it’s just counting clicks, up and down.
NEXT UP, is using the shutter speed number to control motion blur.