Since the original post here was in the nature of "was there any science behind the old paradigm of 'standard focal length equals the diagonal of the format,' before we start applying that to digital sensors too," the topic seems appropriate. Unfortunately, somehow the discussion got sidetracked over the use of the F__m word.
Given that the manufacturers bury any statement of the actual physical dimensions of their sensor in the fine print, and instead use terms like "full frame," "focal length multiplier of 1.6," and "equiv to 28mm-110mm," it's pretty clear they can't discuss it without getting referential to f__m formats either. And it's not like you ever see a 10D or D70 advertised as "supplied with 32.7mm standard lens." (Of course, if they told you what the appropriate "standard" prime lens might be, then they'd have to actually produce one.) Of the three most commonly bandied about examples of a "standard focal length," (50-55 for 35mm, 80 for 6x6, and 135 for 4x5) only one of three is really on the money. Of the other two, one is a good bit short, the other a good bit too long. Oh well, so much for science. Since the most definitive answer so far is that "a hundred years ago some guy eyeballed it," should we be surprised? (You know, maybe that's why all these people go around with their point and shoots held at arms length. They're unconsciously emulating that Victorian gent.) Judging by what focal length lens manufacturers supply with a camera when they do supply a one, the appropriate "standard" lens is a zoom. -------------------------------- Jay Busse Photo Illustrators =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
