Archived posting to the Leica Users Group, 2009/01/28
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi, although I posted this only a month or so ago, here it is again: I never bothered to find out if it applies in manual metering mode - does any one know if that works correctly? Bob Palmieri sent it to me OL in 2005 This is what Canon says about it: The EOS 20D focusing screen is optimized for superior brightness at moderate apertures from about f/3.5 and smaller, compared to conventional ground glass designs. This makes the viewfinder image brighter and easier to focus at those moderate apertures, but the trade-off is that it passes disproportionately more light to the metering system. When a Canon EF lens is mounted to an EOS camera, a variable exposure compensation factor (a program curve, not just a fixed compensation factor) for this phenomenon is fed through the system in order to provide correct metering for all apertures. However, when using a non-coupled manual diaphragm lens as you describe, no such communication takes place, so the responsibility for exposure compensation reverts to you. It's unnecessary to use an external meter. Instead, you can take a series of test shots at the working aperture(s) you plan to use, then analyze the test photos to determine the most desirable exposure compensation factor for each aperture. The 20D's auto exposure bracketing (AEB) function speeds up the process of taking the test photos, and you can use the Info palette in Photoshop to determine the most accurate exposure. If you can standardize on one particular aperture you plan to use (for maximum sharpness, desired depth of field, etc.), that will simplify the calibration process by eliminating the need for tests at other apertures. Cheers Douglas Steve Barbour wrote: > > On Jan 28, 2009, at 2:02 PM, Wayne Serrano wrote: > >> Luggers, >> >> I am inclined or maybe I should say leaning towards a Canon (full >> frame) digital body to make use of the 28/2.8 current, 60/2.8 >> current, 90/2.0 older, 100/2.0 Apo, and 180/2.8 APO lenses. Which >> Canon body I have no idea.... > > > I have a Canon 5D Wayne...I have used a number of Leica R lenses on it... > > remember that there are issues re progressive overexposure as you > close down the diaphragm... > > I am not sure I understand why this is...help someone? > > it's fine if you shoot wide open, > > Steve >> >> >> -----Original Message----- >>> From: George Kase <gkase@ccfc.com> >>> Sent: Jan 28, 2009 12:15 PM >>> To: lug@leica-users.org >>> Subject: [Leica] R lenses on any Digital body >>> >>> Wayne, >>> Get any Canon EOS digital body ( I have a Digital Rebel XT) and >>> Get an adapter for R to EOS mount and you're done. Cheap >>> George >>> >>> >>> _______________________________________________ >>> 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 > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >