It might be important for understanding to see the numbers, Tom. Sometimes discussion or other activities moves in a theoretical way. If you're using several cameras with different format film, sensor, etc, you might want or need to see numerical values to visualize what different focal lengths (that you do not have to work with ...) might present in terms of field of view.
For instance: considering wide angle lenses between the Panasonic L1 and K10D, the DA14 and Olympus ZD 11-22 @11mm net very close to the same diagonal field of view. However, I was curious to find that the photos made with the L1 and the 11-22 looked "more wide angle", so I did some calculations and compared: FL - H FoV - V FoV - D FoV - format 11mm - 78.6 - 63.1 - 91.3 - 4/3-System 14mm - 81.2 - 59.5 - 91.7 - Pentax DSLR In this instance, the 14mm on the Pentax shows a slightly wider FoV diagonally and horizontally, but narrower vertically, than the 11mm on the L1 shows. This made me curious as it seemed a little contraindicative. However, I usually print to an 11x14" image area, which is much closer to the L1's native 3:4 format proportion. I make that adjustment to the K10D's format which nets a different set of numbers: 14mm - 74.5 - 59.5 - 87.1 - Pentax DSLR cropped to 3:4 and now I could see that the 11mm lens on the L1 definitely produces a wider field of view in all dimensions, nearly 5 degrees on the diagonal. After thinking about this and looking at a bunch of pictures, I came to the conclusion that, for me, wide angle views feel wider to my eye when the format proportions are more square, and the 11mm lens on the L1 produces a larger sense of space along with a wider field of view. Now what I know makes sense. In other words, seeing the explicit numbers helped me to understand then interpret what my gut feeling was. Whether that's important to you or not I can't say, but I enjoy understanding stuff like this. Godfrey On Aug 31, 2007, at 9:29 AM, Tom Cakalic wrote: > I suppose that it may be an interesting exercise for some. But > really, > after years and years of using a camera and the experience of looking > through different focal length lenses, doesn't one sort of have a good > approximate idea of what they're going to capture? The variability in > shooting circumstances alone, proximity to subject, etc., makes the > actual > AOV number a little moot. I never think, 'you know lens A has an > angle of > view of X-degress, I think I'll use that one'. > > But if the actual number is important, OK. :-) > >> That's nice if you already own a particular focal length. >> Sometimes, however, one might want to have an idea of FoV numerically >> for other purposes. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
