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Old Dec 31, 2003, 4:24 PM   #1
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Default Depth of Field

Does anyone know what the relationship is between CCD size and depth of field? I'm familiar with this subject when it comes to using an SLR (ie...a film camera) but have been told contrary info when it comes to digital. Specifically, can you control your depth of field (shallow vs deep) via lens aperture, lens focal length and distance from your subjet? Also, are point and shoot digital cameras and digital SLRs similar with respect to the above?

Thanks much
David
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Old Dec 31, 2003, 4:43 PM   #2
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Here is a link to Depth of Fiedl (DOF)
http://www.luminous-landscape.com/tu...ries/dof.shtml

Some digital cameras allow you to control apeture settings and the DOF. My Nikon 5700 allows me full control over the apeture settings. DSLR cameras all have this feature.
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Old Dec 31, 2003, 4:58 PM   #3
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Depth of Field depends on the Focal Length, Aperture, and Distance to Subject.

What's confusing is that you must use the actual versus equivalent focal length for your lens.

For example: the zoom lens on my Konica KD-510z (Minolta G500) is rated at 8-24mm. However, it's "35mm equivalent" focal length is 39-117mm.

So, because a typical digital camera has a much "wider" lens to get the same focal length equivalency in a 35mm camera, it has more depth of field for the same subject distance and aperture.

To get an idea of how aperture, focal length and distance to subject impact depth of field, use this handy online calculator.

It supports popular film and digital camera models, and calculates DOF using true (versus equivalent) focal length, aperture and distance to subject (make sure to use the actual versus equivalent focal length of the camera's lens you are looking at).

http://dfleming.ameranet.com/dofjs.html
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Old Dec 31, 2003, 5:41 PM   #4
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Default Re: Depth of Field

Quote:
Originally Posted by Lozlo
Does anyone know what the relationship is between CCD size and depth of field? I'm familiar with this subject when it comes to using an SLR (ie...a film camera) but have been told contrary info when it comes to digital. Specifically, can you control your depth of field (shallow vs deep) via lens aperture, lens focal length and distance from your subjet? Also, are point and shoot digital cameras and digital SLRs similar with respect to the above?
Take a look at the Depth of Field page of my Nikon Coolpix 4500. It includes all the basics and calculations which might be very helpful.

CK
http://www.cs.mtu.edu/~shene/DigiCam
Nikon Coolpix 950/990/995/2500/4500 User Guide
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Old Jan 1, 2004, 11:25 AM   #5
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Thanks to all who responded.

After posting my question I found this info at Ken Rockwell's site which I thought I would share.

"Depth of Field: Digital SLRs have about the same depth of field as 35mm film cameras. Compact digital cameras have almost infinite depth of field, meaning you can't deliberately blur backgrounds. Why is this? Simple: the tiny image sensors of compact digital cameras (meaning everyone selling for less than $2,000) use much shorter focal length lenses to get the same angle of view. These shorter lenses have much greater depth of field."
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Old Jan 1, 2004, 2:21 PM   #6
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"Compact digital cameras have almost infinite depth of field"...

As with any generalization, don't depend on it without checking your situation.

In trying to help a fellow Minolta Z1 user with her problem in taking sports shots, http://www.stevesforums.com/phpBB2/v...ic.php?t=18937 I used the calculator that jimc recommended for her particular case.

The result is that if she used the Z1 at full 10x zoom (58mm focal length), set the aperture fully open (to get fast shutter speed to stop the action), and focused on a subject at a distance of 10 ft (her estimate of distance), she'd get a DOF of about +/- 3 inches!

Moral: now that we have a generation of digital super-zoom cameras, DOF is something you need to consider.
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Old Jan 1, 2004, 4:41 PM   #7
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Yes Blues you are so right! Take most compact cams off wide, use the zoom and DOF shrinks fast - which can give blurred backrounds sometimes, if you can get far enough back, use zoom and the camera is stable. Another moral, is how good is your AF at high zoom and if it isn't, can the display resolve sufficient detail to get accurate manual focus, or do you need a plug in SVGA laptop! - just some thoughts. VOX
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