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12-05-2006, 11:40 PM   #16
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When shooting landscape I usually focus on something galf a mile away and I use time value mode (Tv) to se the longest possible exposure and get small aperture thus bigger DOF. In this case everything seems in focus (at least on 6mp sensor)

12-06-2006, 05:45 AM   #17
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QuoteOriginally posted by clarenceclose Quote
Thanks for the graphic and the explainations. Then because of the 1/3-2/3 lense DOF, I would assume that has a lot to do with the recommendation, expecially on a landscape shot, that one would focus on something that is 1/3 into the photo, not on infinity, so the DOF of the lense, based upon the aperature setting, would make the photo more effectively focused and give a correct relationship to the eye. i.e. things in the distance are not really in sharp focus nor are things at our feet when we look at a view. ??
Actually, the 1/3rd front 2/3rds behind DOF theory is not quite accurate. If you want to do some calculations, here is an invaluable site where you can enter data of sensor size, lens focal length, aperture and subject distance and the program works out the total DOF, how much is in focus in front of the subject and how much is behind the subject. It is based on a "circle of confusion" of 0.02mm for APS C and 0.03mm for film. "Circle of confusion" or CoC is also explained.

Online Depth of Field Calculator

I would book mark it as it is a very valuable resource. I refer to it extensively.
12-06-2006, 07:22 AM   #18
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QuoteOriginally posted by clarenceclose Quote
Thanks for the graphic and the explainations. Then because of the 1/3-2/3 lense DOF, I would assume that has a lot to do with the recommendation, expecially on a landscape shot, that one would focus on something that is 1/3 into the photo, not on infinity, so the DOF of the lense, based upon the aperature setting, would make the photo more effectively focused and give a correct relationship to the eye. i.e. things in the distance are not really in sharp focus nor are things at our feet when we look at a view. ??
For many landscapes the hyperfocal "spot" is where you want to be. At least to maximise impact. As to 1/3 2/3 thing this also changes as you approach macro distances. It goes to 1:1. but the whole thing is a sliding scale.
Hyperfocal Distance
12-06-2006, 09:50 AM   #19
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QuoteOriginally posted by Lance B Quote
That is very cool! I've got a sort of gut-level feel for dof, but this will be very helpful. Maybe I'll even get circles of confusion figured out, rather than going in circles, confused, as I had been. Thanks!

Julie

12-06-2006, 09:58 AM   #20
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Thanks for all the info and feedback.
12-06-2006, 01:36 PM   #21
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The answer is here (link)

Misconceptions in photographic optics
12-06-2006, 01:44 PM   #22
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QuoteOriginally posted by i.glisin Quote
Another helpful link, thanks. If only I had time to really think about any of this stuff!

Julie
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