Archived posting to the Leica Users Group, 2010/03/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Le 21 mars 10 ? 01:08, John Nebel a ?crit : > > Philippe, > > Rabs put it this way: "it's a medium format camera in a 35mm > package. Delight in its deceptiveness." > > S2 has an f/2.5 lens vs the M's f/1.4 (or f/1.0 or even f/.95) and > is slower due to the larger image circle. The S2 sensor is 45x30mm > and the M's is 36x24mm. > > Maybe it is not correct, but I was thinking of a projector as an > analog, move it farther from the screen and the image is bigger, but > darker. Twice the diagonal size, 1/4 the brightness as the lamp has > to illuminate the equivalent of four of the original images. Makes > me think of the Meno. > 80/2,8 = 40/1,4 = 28.5714 you get different aperture (f) values, but the amount of light is the same as the 'hole' is the same, or am I completely mistaken in the aperture calculation formula? http://fr.wikipedia.org/wiki/Ouverture_(photographie) I would bet that the absence of faster f value on a MF/LF sensitive media lenses results from other considerations such as angle and light fall out in the outer parts of the sheet/film/sensor. At the other end of the size spectrum, if we take the Pana 4/3 pancake you'd get 20/1.7 = 11.7647 a smaller hole, hence slower speeds? unless compensated by the electronics ? with less fall-out issues? I really don't know. Thanks Philippe > John > > philippe.amard wrote: >> Le 20 mars 10 ? 22:25, John Nebel a ?crit : >>> Taken literally that doesn't make much sense; I should have said >>> something like it is lot hungrier for light than a 35mm. >>> >>> Expected, given a slower lens spreading the rays out over a bigger >>> area, but initially surprising with a camera that looks like an >>> R8. Looks aren't everything. >>> >> Could you be more explicit if you have time to, curious minds want >> to understand. >> TIA >> Philippe >>> John >> NO ARCHIVE >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > NO ARCHIVE