DoubleE
01-18-2007, 06:48 PM
Pat asked a question about depth of field so here's a little information and a few pix that hopefully might help.
Depth of field is the area between the nearest and farthest objects in a picture that is acceptably in focus. Several things work together to determine depth of field. First and foremost is the aperature. The smaller the number, the larger the aperature and less depth of field. f1.4 is a huge lens opening and gives very little depth of field. f22 is a very small lens opening and creates great depth of field like you might want in a landscape picture.
The distance from your subject also helps determine depth of field. The closer the lens is to the subject, the less depth of field you'll have.
The focal length also works into the mix. If you zoom back to say around 35mm, you'll get much more depth of field than zooming out to say 210mm. So, the longer the lens, the less depth of field you'll typically have.
The amount of depth of field you'll have will fall 1/3 in front of your focus point and 2/3s behind the focus point. So, you'll have less depth of field in front of your subject than behind.
Here's a picture shot a f1.4 with a DSLR focusing on the middle brush. Very little DOF
http://badgerandblade.com/gallery/displayimage.php?imageid=5718
Same picture (close anyway) shot a f8. You'll see the last brush is pretty much in focus but the first brush is not. Again, more DOF behind the subject than in front of.
http://badgerandblade.com/gallery/displayimage.php?imageid=5720
Lastly, the same shot at f16. Pretty much everything is in focus.
http://badgerandblade.com/gallery/displayimage.php?imageid=5719
Point and shoot cameras are known for having greater DOF that the larger sensor'd DSLRs. So, I typically use my Canon G7 point and shoot rather than my DSLR.
Everything in photography is a trade off. As you stop down to smaller f-stops, your shutter speed will slow down accordingly. So, you'll probably have to use a tripod or brace of some kind to achieve greater DOF.
Experiment by using your camera in aperature priority if it has it or manual to see the different results.
Depth of field is the area between the nearest and farthest objects in a picture that is acceptably in focus. Several things work together to determine depth of field. First and foremost is the aperature. The smaller the number, the larger the aperature and less depth of field. f1.4 is a huge lens opening and gives very little depth of field. f22 is a very small lens opening and creates great depth of field like you might want in a landscape picture.
The distance from your subject also helps determine depth of field. The closer the lens is to the subject, the less depth of field you'll have.
The focal length also works into the mix. If you zoom back to say around 35mm, you'll get much more depth of field than zooming out to say 210mm. So, the longer the lens, the less depth of field you'll typically have.
The amount of depth of field you'll have will fall 1/3 in front of your focus point and 2/3s behind the focus point. So, you'll have less depth of field in front of your subject than behind.
Here's a picture shot a f1.4 with a DSLR focusing on the middle brush. Very little DOF
http://badgerandblade.com/gallery/displayimage.php?imageid=5718
Same picture (close anyway) shot a f8. You'll see the last brush is pretty much in focus but the first brush is not. Again, more DOF behind the subject than in front of.
http://badgerandblade.com/gallery/displayimage.php?imageid=5720
Lastly, the same shot at f16. Pretty much everything is in focus.
http://badgerandblade.com/gallery/displayimage.php?imageid=5719
Point and shoot cameras are known for having greater DOF that the larger sensor'd DSLRs. So, I typically use my Canon G7 point and shoot rather than my DSLR.
Everything in photography is a trade off. As you stop down to smaller f-stops, your shutter speed will slow down accordingly. So, you'll probably have to use a tripod or brace of some kind to achieve greater DOF.
Experiment by using your camera in aperature priority if it has it or manual to see the different results.