the funnel explanation isn't that bad really - if you look at the definition of the circle of confusion (sounds kind of like a secret round table for politicians) on this page http://www.cambridgeincolour.com/tutorials/depth-of-field.htm (close the prompt to register for a newsletter) you'll find that DOF comes from a much similar effect - I'm at a bit of a loss for a better imagebut the general idea is that closing the aperture cuts out the stray rays so to say dang... tell them that after a while it becomes intuitive knowledge and you're too deeply involved in your art to explain it to an outsider
2010/12/3 Walter Gilbert <[email protected]>: > Thanks, Ecke ... that will be helpful down the road, no doubt. > > I guess what I'm looking for is a combination of both. Nothing overly > scientific -- like down to the atomic level, or anything. > > Maybe if I can explain the way I've grasped the concept of the effect of > aperture size on depth of field: I see it as analogous to pouring sand > through a funnel. If you use a funnel with a larger spout, the sand is > going to pile up on the surface underneath it. Whereas, if you use a funnel > with a narrow spout, the sand will spread out on the surface beneath it. > That's how I view light passing through a larger or smaller aperture as it > relates to the focus -- which, as far as I know, is completely false. > > If I could find something that gives a technical explanation, perhaps > formulas, and then an analogy to help it all sink in, it would help me a > great deal. I mostly don't want to sound like an complete idiot when I go > about explaining what I'm doing. :-) > > Thanks again, > > Walt > > On 12/2/2010 6:24 PM, eckinator wrote: >> >> Roman posted this link a while ago and I find it quite useful for >> doing the math. Is it that or are you interested in the underlying >> logic? >> http://roman.blakout.net/?dof >> HTH Ecke >> >> 2010/12/3 Walter Gilbert<[email protected]>: >>> >>> Hi all, >>> >>> Being not particularly mathematically inclined (to put it very >>> charitably), >>> I was wondering if any of you could point me toward a sort of online >>> idiot's >>> guide to understanding and calculating exposure values, depth of field, >>> and >>> other basics along those lines. I figure having at least a loose grasp >>> on >>> details of that nature might be helpful as I dip a toe into the world of >>> analog. >>> >>> I've posted an entry on my photo blog concerning some of the basics that >>> I'm >>> already familiar with, and plan to chart my progress as I go along. >>> Granted, what I've written is geared toward people who know even less >>> about >>> photography than I do (as hard to conceive as that may be), but it can be >>> found here: >>> >>> http://waltgilbert.posterous.com/putting-myself-through-the-old-school >>> >>> It's a first baby step on a long journey, but I'd like to document it as >>> I >>> go along, and share it with anyone who might be interested. So, >>> essentially, I do understand the stuff they probably teach you in the >>> first >>> week of Introduction to Photography 101 -- but largely on an intuitive, >>> practical level. Are there any resources on the web where a simpleton >>> can >>> go to familiarize himself with those principles on a more technical >>> level? >>> >>> Thanks in advance for any help you can provide. >>> >>> -- Walt >>> >>> >>> >>> -- >>> PDML Pentax-Discuss Mail List >>> [email protected] >>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>> follow the directions. >>> > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
