OH, DON’T BE CONFUSED WITH THE TWO DIFFERENT TITLES HERE: “UNDERSTANDING YOUR “F-STOP” OR APERTURE, AND THEN I THROW OUT NEXT: TIPS ON UNDERSTANDING YOUR “DEPTH OF FIELD. THAT IS ALL IN THE SAME. I HAVE GONE OVER YOUR CAMERA CONTROLS, FROM ALL THE DIALS AND SETTINGS ON YOUR CAMERA, TO TALKING ABOUT THE “F-STOP” OR APERTURE ON YOUR CAMERA AND HOW IT CONTROLS THE “DEPTH OF FIELD”. NOW I WANT TO SPEND ONE WHOLE BLOG, TO MAKE SURE YOU HAVE UNDERSTOOD IT ALL, THE F-STOP SETTING AND HOW IT CAN BE ONE OF YOUR MOST PRECIOUS CONTROLS ON YOUR CAMERA.
LET ME JUST SAY THAT WE WILL MOSTLY BE TALKING IN THIS BLOG ABOUT “DEPTH OF FIELD”. “DEPTH OF FIELD” IS ONE OF THE MOST IMPORTANT FACTORS IN DETERMINING THE LOOK AND FEEL OF YOUR PHOTOGRAPH. IT’S ALSO THE MOST OVERLOOKED FOR PHOTOGRAPHERS MOVING FROM A POINT-AND-SHOOT CAMERA TO A DSLR CAMERA. WITH A DSLR, YOU HAVE A HUGE AMOUNT OF CONTROL OVER YOUR DEPTH OF FIELD, AND YOU SHOULD LEARN HOW TO UTILIZE THAT CONTROL TO YOUR ADVANTAGE.
Depth of field refers to the distance (depth) from the focus point that a photo will be sharp, while the rest becomes blurry. A large, or wide, depth of field results in much of the photo in focus. You will see a large, or wide area of depth of field being used mostly in landscape photos:
You will noticed that it is sharply focused in the foreground, as well as all the way to the background of the photo. That would mean that the “depth of Field” is large.
A small or narrow “depth of field” results in a very narrow area being in focus, while the rest of the photo is mostly out of focus:
Neither approach is better or right, and which depth of field to use is up to you. You may have different reasons for choosing a certain depth of field, including artistic effect, bringing attention to a subject, or crisp representation of a scene.
There are four main factors that control depth of field: lens aperture, lens focal length, subject distance, and sensor size. Your sensor is pretty well set, so you won’t have much luck changing that. Your focal length and distance to the subject are usually determined by your choice of composition. So the lens aperture is your primary control over depth of field.
HERE IS THE TIPS YOU REALLY NEED TO MEMORIZE TO FULLY UNDERSTAND THE SETTINGS:
BIG APERTURE = SMALL F-NUMBER = SMALL DEPTH OF FIELD
SMALL APERTURE = BIG F-NUMBER = BIG DEPTH OF FIELD
Let’s give you some examples on your lens, and use those guidelines above:
BIG APERTURE = SMALL F-NUMBER (F1.8, F2, F2.8. F3.5 ETC) = SMALL DEPTH OF FIELD (OR SMALL AREA IN FOCUS)
SMALL APERTURE = BIG F-NUMBER (F22, F16, F11, ) = LARGE DEPTH OF FIELD ( OR LARGE AREA IN FOCUS)
If you will recall, in the previous blog about exposure control, when you use the higher aperture numbers, you will have the need to use slower shutter speeds to have that kind of depth of field. So plan on using your tripod. People may think you are nuts when they see you out in a bright sunny day, using a tripod, but, any photographer will know why you are using a tripod on a sunny day. It’s because they know you are using a higher F-stop number on your aperture, and it’s forcing your camera to use a slower shutter speed, and you are going to get a great photo.
Talking to portrait photographers, I ask them what F-stop they like to use. And it is somewhere in between all the ones we have just talked about. They want to have the background somewhat blurred, but, they don’t want any of the subject blurred at all. I have actually taken portrait photos in a studio before, and the ideal setting was either F5.6 or F8, with the thought that if you were close to the subject, you wanted the whole head to be in focus, but blur out the background. If you went below to F4 you could actually be sharp in focus on the face, but have the ears out of focus. So, remember that setting as you try to take portraits, and you will enjoy the portraits a lot more.