Aperture In Photography
Aperture is one part of the exposure formula. You can change the aperture setting by opening and closing the aperture blades on your lens. The blades form a small hole that light travels through.
Opening the blades up means MORE light will pass through.
Closing the blades up means LESS light will pass through.
Together with shutter speed and ISO, aperture is part of the exposure triangle in photography.
The Focal Ratio
Aperture is measured using the Focal Ratio (or F-Ratio).
An F-Ratio value of f/1.4 is a wide hole compared to f/16 (a small hole).
Aperture & Light
Take a moment and think of your eyelid. It can protect your eye from harsh sunlight. Squinting will keep the light out and opening your eyelid will let the light in
Aperture works just like that!
Just like opening your eyelid wide, using a low aperture number (f/1.4, 2.8 or 3.5) will result in a bright exposure. More light!
A lot like squinting, a high aperture number (f/11, f/16 or f/22) will result in a darker exposure. Less light!
Balance this out for a well exposed shot!
Aperture & Depth of Field
Depth Of Field is the distance between the nearest “thing” and the furthest “thing” that’s in focus.
Shallow Depth Of Field – A Portrait Example
Set your aperture wide (f/1.4, f/2.8 or f/3.5) for a shallow depth of field. Just a sliver of your photo will be in focus. The rest will be out of focus.
Most professional portrait photographers prefer this shallow focus look. The subject’s eye is in focus, and the rest of the image falls out of focus quickly.
Large Depth Of Field
Close up your aperture (f/8, f/10 or f/13) for a large depth of field. A larger portion of your photo will be in focus.
For example: A landscape photographer will use a larger depth of field to get as much of the scene in focus as possible.
They may close their aperture up to f/22 to get all the mountains, fences, and streams in focus.
Minimum And Maximum Apertures
Photographers think of minimum and maximum aperture as limits. A lens can only “open up” or “close up” so much!
Different lenses are going to offer different maximum apertures.
All lenses are not created equal!
The maximum aperture is the limit of HOW WIDE the aperture blades can open to.
A lens may have a minimum aperture of f/1.4, f/2.8, f/3.5 and so on.
Your minimum aperture is the limit of how CLOSED UP the blades can get.
Most lenses have no issue with this and can close to f/16 or even f/22.
By learning and taking control of your aperture setting, you can experiment with light and different depths.
You can draw attention to the things that you feel are important!