An interesting article by Lrs Kjellberg investigates Improved sharpness using various aperture settings on photographic lenses. The issue is not quite as linear and simple as one might at first expect. It is obvious that a completely open lens will lead to a less sharp results. (This is why we focus with the lens wide open and then stop it down if desired?) It is interesting to find out however that at apertures beyond f8, diffraction becomes an issue, making the images less sharp again. (This is valid for the plane of focus only. The depth of field, or even margin of �error� is much greater at f22 than it is at f1... of course.) The author provides great illustrations to explain all of this very well.
Very true Witold, in fact I read somewhere recently (I need to find that article) that some digital SLR cameras (like my new one) are even more sensitive to small (closed down) apertures. Darn those Physics! If I come across that article again I'll let cha know.
Posted by: Pat on July 1, 2002 07:23 PMhmm, this is not always true. every lens on this planet has a different "best" apperture. i stumpled the other day over an extensive list showing the ideal apperture for _every_ olympus lens ever made. a 1.2 50mm would have 11 and a 1.8 50mm may have 8 as the best apperture (i just made those numbers up, just to prove my point). this is fine for analog SLR, but digital SLRs facing another problem: 1 or 3 chips? if 1, square, round or hex light detectors on the chip... also different focal lengths due tue smaller chips.
that's enough nerd talk for now...
Posted by: Joergen on July 2, 2002 12:05 PMYou are so right. The article seemed a bit too general to make sense. Every lens is a different animal. I completely, completely agree.
Posted by: witold on July 2, 2002 12:11 PM