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Old 08-24-2006, 11:51 AM   #16
knightly
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for 1/3" chippers, I'm going to see if I can get a DoF chart for a super 8 camera (about the same capture size). I can't seem to find any laying around the web that are useful and easy to understand. Maybe someone around this board has one laying around they could link
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Old 08-24-2006, 04:30 PM   #17
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Found one:

http://www.filmshooting.com/community/articles/dof.php
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Old 09-04-2006, 07:18 AM   #18
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Quote:
Originally Posted by clive View Post
Interesting conversation, but just thought that I'd mention that you can buy cheap ND filters for the front of most camcorders.

The use of ND (Neutral Density) to decrease the amount of light, which then allows you to open the aperture and thus decrease depth of field, is the most effective way to control depth of field.
Bit late... but better late than never. The clip I shot was using a circular polariser which pretty much achieves the same thing.
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Old 09-04-2006, 07:08 PM   #19
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Quote:
Originally Posted by knightly View Post
pulls cord - "The Google Says, .33 inches = 8.38200 millimeters"

So you're basically shooting 8mm with half the effective resolution and less grain.
That is not correct, because the given size of the CCD means the diagonal, not the width.

width = a
height = b
diagonal = c

for 4:3 ratio 1/3" CCD:

a / b = 4 / 3 -> a = 4 * b / 3
c = 8.4667 mm (1 inch = 25.4 mm)
c² = a² + b²

b = sqr(0.36 * c²) = 0.6 * c = 5,08 mm
a = 4 * b / 3 = 6,773 mm

for 4:3 ratio 1/4" CCD like Canon GL-2 / XM-2:

a = 5,08 mm

btw: 35 mm film has only a usable width of 24.9 x 18.7 mm (negative) or 21.3x17.8 mm (positive), anamorph 2x

Here is an DOF example picture I took with the Canon XM-2 (GL-2) using 1/50 f2.4 and half zoom (10x):

Last edited by freezer; 09-04-2006 at 07:41 PM.
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Old 09-06-2006, 10:38 AM   #20
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Just to throw another wrench into the gears, DOF is also somewhat subjective. DOF is based on circles of confusion, which quantify the acceptable amount of blurriness for a specific lens, medium, etc. There is really only one point of precise focus, with a range of acceptable focus. Therefore, in order to measure DOF, you must determine what is acceptable focus (minimum circle of confusion diameter). With mini-DV, which is rather low resolution, you might be able to use a relatively large circle of confusion (CoC), for an even wider DOF. Whereas, with HDV or other HD formats, the CoC might have to be smaller, which might enhance selective focus somewhat, even with the same lens and CCD size. (i.e. If the sharp parts of the image are sharper, the slightly out of focus areas will look noticably softer)
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Old 09-06-2006, 10:47 AM   #21
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One more thing ... regarding the article citing a table of hyperfocal distances ... "depth of focus" is not the same as "depth of field". Most of us don't care about depth of focus, but depth of focus refers to the area behind the lens (the CCD or film plane), and the depth of sharpness measured there (measured in millimeters or micrometers). It matters to you if you are a scientist working with specialized optics for microscopy, or if you're designing a camera. For most people on this forum, depth of field and selective focus are the operative terms.
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