Light Techniques
F Stop Settings Explained
Article taken from Chapter 1, Understanding How To Read Light, page 13 of "Advanced Digital Photography" by Amy Renfrey.
What is an F stop? Understanding f stop is an easy thing. An F stop is a numerical measurement of Dynamic Range. F stop simply pertains to how much light exposure the digital camera is getting.
You may remember in “Digital Photography Success” how I explained what aperture meant. To reiterate; aperture is the size of the lens opening that lets the light in.
The smaller the opening the less light comes in. The larger the opening the more light comes in. Think of aperture as a pupil that dilates when it’s dark and becomes smaller when it’s light.
Larger Aperture Small Aperture
(Small F Stop Number) (Large F Stop Number)
Each measurement of how open or how closed an aperture is was given a name. That name is an F Stop. The total aperture of the lens is called a range of f stops.
And just to make matters confusing F Stops are opposite to how far the lens is opening. For example to let in a lot of light and make the aperture larger, it might be an F Stop of 4 (F 4).
On the other hand, if you want to close light out, the aperture might shrink to a small circle, only letting a small amount of light in, therefore it might be as F Stop of 22 (F 22.)
Keep in mind the lower the number, the wider the aperture, the wider the aperture, the more light comes in. For example, an f stop of 2 or lower means the lens opens up real wide to let lots of light in. You’d use these low settings for night time photography to get as much light in as possible.
And if you were photographing something very bright, such as a landscape on a bright summer’s day, you’d possibly set the F stop at f 16 or f 22 for example so it doesn’t overexpose the photo. I’ll explain more in my f stop scale diagram in a moment.
The smaller the opening, the greater the depth of field.
It is a very good idea, if you are still learning with your digital photography, to take notice of the F stop your auto setting sits at when you take photos.
To further clarify this lets have a look at this diagram to see how the shutter in the camera relates to the aperture/F-Stop.
The above diagram is of a standard camera; F 2.8 being the largest aperture setting and F16 being the smallest aperture setting. You can see the workings at each stage. The higher the number the less light gets in. The lower the aperture setting the more light gets in.
If you want to learn more about f stop and how it impacts your photography, you'll find Advanced Digital Photography the ideal ebook to show you how to create magical photos. To see more, just view the table of contents for it at... Advanced Digital Photography
Article by...
Amy Renfrey
Digital Photographer, Digital Photography Teacher & Author
