Digital Photography Tip Number 26....Small Aperture Value Means Smaller Depth Of Field
Tip #26) Small Aperture Value Means Smaller Depth Of Field.... When you use a small aperture value like F1.4 or F2.8 or so, you will get the least depth of field(focus) and your focus point will be more critical. It can be confusing to alot of people when they think about aperture values. A small aperture value like F1.4 means that the lens aperture is fully open, or the largest aperture opening, if F1.4 is your lenses smallest aperture value, which lets in the most light, but causes the depth of field to be reduced.
This activity will only work if you have bad eyes and need glasses or contact lenses to see far, so you people with good eyes are out of luck, you can't try this fun activity. To start, grab a piece of paper and a pin or tack, and poke a small hole in the paper. Take off your glasses or contact lenses, and then look through the small hole, with the paper as close to your eye as possible. You should be able to see distance objects clearly, without your glasses!! Now you don't have to wear glasses anymore, just stick pieces of paper with small holes in front of your eyes and you have 20/20 vision again, who needs glasses or Lasik surgery, you have your paper with small holes to make you see perfect again.
Similar Confusing Terminology
If you did the activity above, you should understand a little better, that a large aperture value like f/22, gives you much more depth-of-field(focus) than a small aperture value like f/1.4. A small aperture value like f/1.4 allows a lot of light into your camera, like you can see in the photo collage above, but a shorter depth-of-field(focus). Something that has similar confusing terminology is electrical wire. A size 28 gage wire is much smaller than a 8 gage wire. So to sum it all up, you just have to remember a small aperture value like f/1.4, gives you shorter depth of field(focus), but a larger aperture opening and more light into the camera.
Depth-Of-Field Preview Button
To help you see what the depth-of-field will be at your cameras current aperture setting, most digital SLR's have a depth-of-field preview button on the lens or camera body. When you are looking through the viewfinder, you press the preview button and the lens aperture will go to the current setting allowing you to see the depth-of-field.
Many times you want a short depth of field, like for closeup flower photography to blur out the background, like in the photo above, so you should use the smallest aperture value you can. Other times for landscape scenery photos like the panoramic photos in our Switzerland Photography page, you want to use a large aperture value to get as much depth of field as possible to make everything in the photo clear, and that's what tip #27 is about, so click next tip below.