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04/21/2003 10:49:35 PM · #1 |
Okay, I got it - I have read it everywhere. Aperature affects depth of field, aperture affects depth of field, ap... you get the idea (and yes, I have read two different spellings of the word aper(a)ture).
My question is this, if aperature affects depth of field so much, why do I have a manual focus distance settings (.5m, 1m, etc.)? What wins?
Please help,
Confused in Carolina
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04/21/2003 10:55:47 PM · #2 |
your focus distance doesn't affect depth of field... it just shifts your sharp area in or out...
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04/21/2003 10:57:43 PM · #3 |
Depth of field and focal distance are two different things. Focal distance is the distance to the focal plane (the plane of highest focus). Depth of field is the distance on either side of the focal plane where there is acceptable focus. A small aperture (larger F#) increases the depth of field, so that a larger part of the background and foreground is in focus. A large aperture (smaller F#) decreases the depth of field, so that there is less acceptable focus surrounding the focal plane. This setting is good for portraits, where the person is in focus but the background is blurred.
Depth of field is related to a number of other factors (sensor size, lens properties etc) which varies from camera to camera. Your S75 has a limited ability to control DOF based on aperture settings...even at a large aperture you will get a large DOF due to the small sensor size.
Still, hope that helps.
Message edited by author 2003-04-21 23:02:13. |
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04/22/2003 07:41:22 AM · #4 |
to put it simply - say you set your aperture for a narrow DOF and hten you focus on something 3 feet away. now the spot you focused on, a teeny bit behind it (farther from you), and a teeny bit in front of it (closer to you), are gonna be clear.
now focus on something 10 feet away. same thing happens. THE SPOT YOU FOCUSED ON, and a teeny bit behind and in front of it, will be clear - everything else blurry.
say you set it for a wide DOF, and focus on the same stuff. now the zone of clarity is going to be MORE than a teeny bit behind and in front.
think of the aperture as how wide your zone of clarity is and your focus as 'where you put that zone of clarity in the scene.'
make sense?
For more info, see my DOF tutorial under Learn menu ..
Message edited by author 2003-04-22 07:42:19.
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04/22/2003 07:50:46 AM · #5 |
You do have a way with words, mag! Even I thought I totally understood it, and then you posted this. Now it makes even more sense!
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04/22/2003 08:24:17 AM · #6 |
:-D
Originally posted by KarenB:
You do have a way with words, mag! Even I thought I totally understood it, and then you posted this. Now it makes even more sense! |
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04/22/2003 10:43:40 AM · #7 |
It's kind of like an imaginary box in front of your camera. The focal distance is how far away the box is from your camera. Your depth of field is how long the box is. As mentioned above, check out the excellent tutorial on this under LEARN in the bar above.
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04/22/2003 11:11:16 AM · #8 |
Not completely true:
The further you are from the focus point, the MORE depth of field you have given a constant aperature. You may only have inches when the subject is within 3 feet, but when the subject is at 12 ft, you may have a foot of DOF to work with.
Originally posted by magnetic9999:
to put it simply - say you set your aperture for a narrow DOF and hten you focus on something 3 feet away. now the spot you focused on, a teeny bit behind it (farther from you), and a teeny bit in front of it (closer to you), are gonna be clear.
now focus on something 10 feet away. same thing happens. THE SPOT YOU FOCUSED ON, and a teeny bit behind and in front of it, will be clear - everything else blurry.
say you set it for a wide DOF, and focus on the same stuff. now the zone of clarity is going to be MORE than a teeny bit behind and in front.
think of the aperture as how wide your zone of clarity is and your focus as 'where you put that zone of clarity in the scene.'
make sense?
For more info, see my DOF tutorial under Learn menu .. |
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04/22/2003 11:15:53 AM · #9 |
| Hmmm...I thought my explanation was wicked-awesome ;). Maybe I shouldn't teach at a special school? |
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04/22/2003 11:44:06 AM · #10 |
| Don't fuss, you are both right...the "box" just gets longer the farther away it gets...they are BOTH useful descriptions thank you. |
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04/22/2003 12:30:22 PM · #11 |
Originally posted by GeneralE:
Don't fuss, you are both right...the "box" just gets longer the farther away it gets...they are BOTH useful descriptions thank you. |
Amen! I often need things said in three different ways before I understand it. Just ask my wife.
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