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09-28-2008, 06:50 PM   #31
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I told you so...

Just for the record, I warned against opening the DOF can of worms. If there is anything more confusing than explaining what determines perspective, it is explaining the intricacies of depth of field. Now the worms are loose...

Steve

BTW...Six months ago I was a firm believer that wide-angle lenses would give you exaggerated perspective and greater DOF as a property of the optics. Based on the challenge of some forum members, I set up the test images and proved myself wrong on both counts.


Last edited by stevebrot; 09-28-2008 at 06:58 PM.
09-28-2008, 07:06 PM   #32
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QuoteOriginally posted by baw Quote
I'm fine with a statement like: For a given FOV DOF is the same for different focal lengths. At least it seems to be so.
My point is that the article clearly implies that DOF is independant of focal length, which is nonsense.
I'm a bit surprised by this article. I had a high regard for Luminous Landscape....
Depth of field is a relationship between the size of the aperture and the reproduction ratio, nothing more.
Focal length is not part of the relationship.
And Steve, yer welcome...
09-28-2008, 07:16 PM   #33
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In case anyone is interested, here is a link to the other thread where all of this stuff was discussed in detail a few months ago:
https://www.pentaxforums.com/forums/general-pentax-photography/30632-85mm-vs-...ification.html
Steve
09-29-2008, 01:51 AM   #34
baw
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DOF

QuoteOriginally posted by Wheatfield Quote
Depth of field is a relationship between the size of the aperture and the reproduction ratio, nothing more.
Focal length is not part of the relationship.
Seems you have invented a whole new defintion of DOF. Perhaps you can explain what the relationship is. It's also unclear to me what you mean with reproduction ratio.

DOF is normally defined as a range of distances in front of the lens within which objects are reproduced ACCEPTABLY sharp in the resulting image.
See this page with a number of similar definitions and references.

09-29-2008, 02:29 AM   #35
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One was taken with a Sigma 105mm macro at about 2 to 3 feet.

One was taken with a 560mm astro scope barlowed to an effective FL of 1100mm (about 30x magnification) with extensions to move focus closer. About 25 feet or so.

Can you tell which is which?

Last edited by wildman; 12-26-2008 at 01:00 PM.
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