On Wed, November 18, 2009 15:44, ADavidhazy wrote: > A little more photo talk FYI - my students struggled with the answer to > this question. How would you > or your students do? > > QUESTION: If two lamps provide a level of illumination that produces two > stop underexposure of a > given scene, how many ADDITIONAL lamps are needed to provide a level of > illumination that will > result in a properly exposed scene? > > 1 2 3 4 6 8 > > circle one choice Two stops is 4x the light, so you need 4x the lamps, 8 lamps total. So that's 6 additional lamps beyond the two you started with. > To find out the answer (you can work out the reasons!) (or ask!) follow > this link: > http://people.rit.edu/andpph/a-pix/lamps-1.jpg > > BTW, I have another hoky question for you: How wide is 35mm film? Grant and Mrs. Grant? Oh, wait, wrong question. The film strip is actually 35mm wide -- 24mm of image area plus 11mm of sprocket and border. -- David Dyer-Bennet, dd-b@xxxxxxxx; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info
