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Old Jan 29, 2007, 11:25 PM   #1
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For me, being able to shoot with a narrow DOF is the biggest advantage to moving up to a low-cost dSLR. Now, it seems to me that using a narrow DOF to emphasize an area of the photograph would be as great of a 'feature' as just about any other aspect of taking a picture. There are so many times I find myself wishing I could use DOF to put more of a focus on what element/subjectI want the picture to show. But, then again, I haven't ever used a dSLR, so I don't know, maybe its not used as much as I think it is.

What is your take on this? Out of the total pictures you take, what would you say is the percentage that you take using a narrow DOF to emphasize something in the shot?
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Old Jan 30, 2007, 2:10 AM   #2
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boy you're going to get wild swings on this answer. A landscape photog will very rarely use shallow dof. Wildlife and sports photographers use it constantly. I happen to be a sports photographer so I'd say about 85% of my shots are shallow dof (f2.8 or wider).
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Old Jan 30, 2007, 4:53 AM   #3
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Similar to John I guess as I do similar work (not as good but getting there) so most of my shots are f3.2 or 2.8 (I use 3.2 as it has a much higher hit rate than at 2.8 for fast moving sport so it is a worthwhile trade off).

I also use narrow dof in portrait to isolate the subject from the background when it helps.

As John rightly says landscape shots will very rarely have a narrow dof so when shooting landscape will generally go out to f8+ dependent on the focal length.
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Old Jan 30, 2007, 9:19 AM   #4
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What isthe 'true' purpose of the aperature setting? Is itfor setting the DOF? I thought it was simply for compensating for brightness or darkness. As I understand it, it does both. But, what if you want to increase the brightness of a picture without affecting the DOF?
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Old Jan 30, 2007, 10:02 AM   #5
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Contriver wrote:
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What isthe 'true' purpose of the aperature setting? Is itfor setting the DOF? I thought it was simply for compensating for brightness or darkness. As I understand it, it does both. But, what if you want to increase the brightness of a picture without affecting the DOF?
heh heh! Now you're getting into "photography"! BTW, I don't know the answer to your question as I'm still learning about photography myself. But it sure is fun figuring out the answer.

Russ
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Old Jan 30, 2007, 10:15 AM   #6
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Contriver wrote:
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What isthe 'true' purpose of the aperature setting? Is itfor setting the DOF? I thought it was simply for compensating for brightness or darkness. As I understand it, it does both. But, what if you want to increase the brightness of a picture without affecting the DOF?
The aperture setting affects both dof and lighting, so I guess both are 'true' purpose, it just depends on what you need it for. When you use wider aperture (lower f-stop number) it has an effect of narrowing the depth of field. You can't do anything about that.


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But, what if you want to increase the brightness of a picture without affecting the DOF?
This could come into play when you want a wide depth of field(small aperture), but want to freeze the movement with a faster shutter speed(which usually needs a wide aperture). In this case, lighting comes into play. You need to make sure you have enough light.

I shoot mostly landscape, so I usually (90%) use wide depth of field (with a wide angle lens). I use narrow depth of field for portrait and sports.

When I started shooting DSLR last year, I noticed that much of photography is reacting-to or controlling the amount of light. There are times you can control them, like in a studio, and there are times you just have to compensate for them one way or another (with better lenses, external flash, filters, or camera settings).


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Old Jan 30, 2007, 11:42 AM   #7
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Contriver wrote:
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What isthe 'true' purpose of the aperature setting? Is itfor setting the DOF? I thought it was simply for compensating for brightness or darkness. As I understand it, it does both. But, what if you want to increase the brightness of a picture without affecting the DOF?
The aperture regulates the amount of light (brightness) coming into the camera (you said brightness/darkness). The setting of the aperture also controls the depth of field. so yes, it does both.

To increase the "brghtness" (amount of light), you can sometimes (in manual operation only), simply slow down the shutter. Some cameras allow you to "shift" the shutter for example while leaving the aperture alone.

Caution: most cameras in automartic operation (will not allow slowing th shutter without alterinf the f/stop).

You can also employ a ND filter (in full mnaul operation) to slow the shutter

Another catuion: it is nearly impossible to do what you ask in your last question.. You either have narrow DOF, "normal" or adeepDOF.




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Old Jan 30, 2007, 1:03 PM   #8
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There are 3 things that affect exposure weather film or digital. Aperture, Shutter Speed and ISO. You can have several different settings of all three that will give you a correct exposure for an image. It just depends on what you want the image to say.
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Old Jan 30, 2007, 10:23 PM   #9
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Contriver wrote:
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What isthe 'true' purpose of the aperature setting? Is itfor setting the DOF? I thought it was simply for compensating for brightness or darkness. As I understand it, it does both. But, what if you want to increase the brightness of a picture without affecting the DOF?
To do this, your shutter has to be open longer, or the sensitivity (ISO #) has to be increased, or both. Some cameras (Pentax DSLRs come to mind) have a setting which automatically increases the sensitivity to give you a reasonable shutter speed. This sometimes means an increase in noise, though. Everything in photography involves a tradeoff, and only experience combined with good advice from those who are experienced will get one to the point of knowing which tradeoff to make for the type of shot you are taking.

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