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Old Oct 26, 2007, 10:56 AM   #1
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Hello All,

I am still new kinda new to Photography....I say kinda because I am a videographer / cinematographer.

My question....How do I achieve a good depth of field?

I have a K10D....what settings do I need to change? Focal Length, ISO? I am still new to this camera.

Thank you all.
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Old Oct 26, 2007, 10:57 AM   #2
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f stop?
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Old Oct 26, 2007, 11:05 AM   #3
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Depth of Field is controlled by Aperture (smaller apertures, represented by higher f/stop numbers give more depth of field), Focus Distance (the further you are from your subject, the greater the depth of field), and focal length,

See this handy Depth of Field Calculator to get a better idea of howthese factors (focus distance, focal length, and aperture) worktogether for depth of field purposes. You can plug in your camera model, aperture, and focus distance and it will calculate the area of acceptable sharpness.

Keep in mind that if you use a longer focal length (or more zoom), you'll need to be further away for your subject to occupy the same percentage of the frame.

http://www.dofmaster.com/dofjs.html

Be careful of shutter speeds if you're trying to achieve more depth of field. If you use smaller apertures (higher f/stop numbers) for greater depth of field, you also require slower shutter speeds for proper exposure (which can cause motion blur in lower light if ISO speed is not fast enough).

Using smaller apertures can also impact flash range.

You also need to take lens characteristics into consideration. Most lenses tend to be sharper a couple of stops down from their widest aperture setting (lowest f/stop number). For example, a lens with a widest available aperture of f/2.8, may be considerably sharper at f/5.6.

You can start getting softer images if your aperture is smaller verus wider, too. if you set your aperture too small (i.e., f/16 or so), you'll start getting softer images from diffraction with many lenses. So, it's usually best to avoid aperture extremes, depending on lens quality/characteristics and what you're trying to achieve.

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Old Oct 26, 2007, 9:29 PM   #4
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welcome to the board,
as far as i know all of pentax's dslr's have a DOF preview switch on the ''on/off'' button. you can press this and it will stop down the lens to the aperture you have set the lens to and it will show you in real time what is/isn't in focus. using this method takes experience to see/understand what you are seeing especially at f-stops of f11 and above.

roy
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Old Oct 26, 2007, 9:31 PM   #5
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mlcinema wrote:
Quote:
f stop?
oops,,, f stop???

yes!! that's what you use for dof..

roy


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Old Oct 26, 2007, 9:49 PM   #6
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What Jim and Roy said!!



Dawg
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Old Oct 26, 2007, 10:06 PM   #7
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I have the K100, not the 10, so I'm not sure of the procedure. On the K100D you can push the power switch an extra bit and get the aperature to stop down to get a DOF preview. Unless it's VERY bright out it can be useless as it's too dark to really see clearly, but it's an option. Very useful when doing close up/marco work as the difference in the very shallow DOF you see through the viewfinder (which is wide open when you're composing/focusing) vs what you can make out with the ap stopped down is pretty evident..
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Old Oct 26, 2007, 11:04 PM   #8
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What Jim said.

As far as the K10 and the depth of field preview - it works the same way it does on the K100 (and I do use it mostly for macro, where DOF becomes so important). For most walk-around pictures, I just pay attention to what aperture numbers come up (or what I set) and don't bother using the preview that much any more (I did for a while). As was stated, once you start setting small apertures (larger f numbers, such as f22) the lens opening becomes small, less light comes through the lens and the viewfinder is much darker.

There's aninteresting difference between the K10 and the K100 - both have the capability of previewing the DOF - Pentax calls that "optical preview." Both cameras also have the capability of showing a preview of what the scene looks like on the LCD screen - Pentax calls this "digital preview." They both do this the same way - by turning the power switch to the funny-looking round symbol next to "on." There's a setting in the custom menu that allows you to change between digital and optical preview. What's different is that the default setting in the custom menu - the K100's default setting is for digital preview and the K10's default is for optical preview. It seems that Pentax assumes that K10 users are more likely to want to check DOF, while more K100 users would want to check exposure and what the picture might look like on the LCD.
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