PhotographyTips.com - the #1 guide to better conventional and digital photography Become a Member iPhone Posing GuideGuide to Posing the Female Model BookGuide to Posing the Model CD
Search
Login

Member Login

Find us on Facebook
Follow us on Twitter
Find us on Flickr
Connect with us on LinkedIn

SPONSORS

Sell Photos Online

FEATURED SITES


Depth of Field

The aperture's influence on focus


The moderately shallow depth of field in this image has the subject in focus while foreground and background are less sharp, ensuring that your eye is drawn directly to the subject.
The moderately shallow depth of field in this image has the subject in focus while foreground and background are less sharp, ensuring that your eye is drawn directly to the subject.

You have undoubtedly seen photographs in which every element from foreground to background is in sharp focus, and other pictures in which only the subject is in sharp focus while everything else is blurry. The former picture is said to have more depth of field than the latter, which has shallow depth of field. The zone of the picture that is in focus is the picture's "depth of field."

You may hear someone incorrectly refer to it as "depth of focus," which is a different thing. (See Depth of focus for more information.)

APERTURE CONTROLS DEPTH OF FIELD

An image’s depth of field is controlled by the camera’s aperture. (If you haven’t already done so, we suggest you refer to our section on Aperture to gain an understanding of what it is and how it functions before continuing on in this section.)


Small apertures such as ƒ/16 and ƒ/22 give more depth of field than do large (wide) apertures like ƒ/2 or ƒ/1.4. This means that more of your picture will be in focus at an aperture setting of ƒ/16 than there will at an aperture setting of ƒ/2. If you keep in mind the simple principle that a smaller aperture causes more of your picture to be in focus, then you are on your way to taking control of your photography.

This lens is
This lens is "wide open" at its maximum aperture of f1.4 which provides very shallow depth of field.

Notice how selecting f16 greatly reduces the size of the aperture. This small opening provides the maximum depth of field for this lens.
Notice how selecting f16 greatly reduces the size of the aperture. This small opening provides the maximum depth of field for this lens.

HOW TO ADJUST FOR GREATER DEPTH OF FIELD

How do you change your aperture setting for more depth of field, that is, to have more of your picture in focus, and still maintain proper exposure? Let’s assume your light meter has provided you with an exposure reading of your subject of 1/500 sec at ƒ/5.6, which means you would use a shutter speed of 1/500 second and an aperture setting of ƒ/5.6 to correctly expose your subject on the film or your digital camera's sensor. Now, think of the simple principle we asked you to keep in mind – “a smaller aperture causes more of your picture to be in focus.” An aperture of ƒ/5.6 is a medium-sized opening, not a small one at all, therefore only a moderate zone will be in focus at the light meter’s recommended exposure setting. To achieve greater depth of field, you must change the setting. We know that ƒ/16 is a very small aperture, so go ahead and select it, but remember (this is critical), whenever you change your aperture, you must also change shutter speed to maintain correct exposure.


ƒ/16 is so small an opening that much less light will reach the film or sensor, so you must make your shutter stay open for a longer time to achieve proper exposure. And how do you know what shutter speed to select? Count the number of ƒ-stops you changed that will decrease the amount of light reaching the film and change your shutter by the same amount of stops to increase the light. You went from ƒ/5.6 to ƒ/16. That is a change of three stops, namely ƒ/8, ƒ/11 and ƒ/16. So, lower your shutter speed setting by three stops, from 1/500 sec to 1/60 sec. Your new setting, which will still you give you proper exposure of your subject but with more depth of field, is 1/60 sec at ƒ/16. That’s it.

If your camera is equipped with through-the-lens metering that displays various correct exposure settings as you change the shutter or aperture settings, you can make it even simpler by first selecting an aperture of ƒ/16 as you are about to take your light meter reading, and then adjusting only the shutter speed until the meter shows a correct exposure reading.

Maximum depth of field has foreground pebbles and background mountain rendered sharply.
Maximum depth of field has foreground pebbles and background mountain rendered sharply.

These images clearly show the difference between shallow depth of field (upper image taken at f/1.7) and great depth of field (lower image at f/16). Thanks to photographer Chris Hardwick for sending them in.
These images clearly show the difference between shallow depth of field (upper image taken at f/1.7) and great depth of field (lower image at f/16). Thanks to photographer Chris Hardwick for sending them in.

IS THERE MORE TO KNOW?

“Is that all there is to it?”, you ask. It’s not all, but that’s enough for now. If you have firmly caught on to the principle that a smaller aperture causes more of your picture to be in focus, and you use the principle in taking pictures, you are well on your way.

Soon, however, you will begin wondering if it is possible to control precisely how much depth of field there is in your pictures, and whether you can have only the background or the foreground in focus using depth of field. Yes, you can do both, and we explain these techniques further on in this section of PhotographyTips.com.

But, let's take it one step at a time. We suggest you make your next stop at the section entitled How much will be in focus and go from there. You may want to jump there right now or wait a bit, practicing what you have picked up here first. Our recommendation? Learn from one of our tips, put what you’ve learned into practice so you better understand it, then come back for more advanced tips. You will be better prepared for the next step. We will be here waiting for your return.


This is what an aperture of f8 looks like. This aperture provides medium depth of field.
This is what an aperture of f8 looks like. This aperture provides medium depth of field.
Further information...

How much will be in focus?

Controlling depth of field

Depth of field preview

Hyperfocal distance
Related topics...

Depth of focus