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Old Sep 7, 2010, 8:59 PM   #1
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Default canon powershot SX20is DOF

so i have been trying and trying every possible way to get a shallow DOF. I have failed. I have the Canon Powershot SX20is.. a superzoom. I know all about aperture and all that jazz, but i cant get any decent bokeh affects.

In macro and supermacro mode, obviously the DOF is the shallowest. And i know that as i zoom in AV mode (or any mode), the aperture will be larger.

My question is, is there anyway to achieve a shallow DOF on my camera without having the subject matter way in front of the background?

Any help would be appreciated, or if there is another thread directly relating to this one that you can point me to.

Thanks!
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Old Sep 7, 2010, 9:30 PM   #2
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Depth of field is a function of distance (closer yields less DOF), aperture (more open yields less DOF) and focal length (longer yields less DOF). The Canon website shows your lens has a range of 5.0 mm (W) - 100 mm (T) f/2.8-5.7. so your best result would be 100 mm at f/5.7 with the subject close to the camera. That may not be good enough for your taste however but there is little you can about it with this type of camera.

The 35mm equivalent of 28-560mm is just marketing hype and has nothing to do with the optical laws that you are encountering.

Last edited by Bob Nichol; Sep 7, 2010 at 9:36 PM.
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Old Sep 7, 2010, 9:34 PM   #3
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Shallow DOF on a small sensor camera is going to require your longest focal length, and largest aperture. How shallow you can get, depends on the actual focal length of the lens, and its maximum aperture. Bokeh is another area, related to shallow DOF, but considered more on the lines of a quality issue, and is very much lens related.

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Old Sep 7, 2010, 9:42 PM   #4
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See http://www.dofmaster.com/dofjs.html for an online calculator.

SX20 IS 100mm f/5.7

Subject distance 10 m
Depth of field Near limit 9.73 m Far limit 10.3 m Total 0.56 m

Subject distance 100 m
Depth of field Near limit 78 m Far limit 139.4 m Total 61.4 m
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