Archived posting to the Leica Users Group, 2001/05/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 5:28 PM -0400 5/4/01, Isaac Crawford wrote: > > Off line I've received several very interesting replies regarding the >> Heliar. Including some very technical and interesting points about >> vignetting, light fall off and other issues at various apertures. These >> might cause metering issues. > > That's some serious light falloff if its affecting a center weighted >metering system!:-) > >They also me to understand the lens. Superwides >> are attractive little creatures, because they're unusual. But they do have >> their foibles. > >True enough... >> >> Dave In my experience super wides need a little more exposure, partly due to the fact that since such a large solid angle is imaged and both near and far are often important components of the image, the contrast range tends to be greater than with longer lenses. Combine this with the larger amount of light falloff to the corners, and you then need even a bit more exposure overall. I usually give 1/3 to 1/2 stop more exposure with slide film and another 1/3 with negative film when using the 15 or 12, compared with metering the same surface with a 50. The 21's generally need an additional 1/3 stop at most.