Archived posting to the Leica Users Group, 2009/01/29
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Thanks Aram it would be nice if Canon provided a firmware update to switch the function off Cheers Douglas Aram Langhans wrote: > The same problem exists in manual metering mode, at least with my Rebel > XTi. > If using manual mode, you must meter at full aperture, then, if you stop > down say 3 stops, you then must slow the shutter down the appropriate > amount > and ignore what the meter is telling you. It will show that you are > underexposing, when in reality you are properly exposing. A real PITA, but > it works. AE mode is easier if you use the +/- compensation and are always > going to use a particular f-stop for a series of photos. However, if you > are stopping down many stops for DOF purposes, the manual mode might be > your > only choice because the +/- 2 stop range of the Rebel in Aperture mode > might > not be enough to compensate. > > Aram > > > > >> From: Douglas Sharp <douglas.sharp@gmx.de> >> Subject: Re: [Leica] R lenses on any Digital body - exposure problem >> To: Leica Users Group <lug@leica-users.org> >> Message-ID: <4980DFAA.5090609@gmx.de> >> Content-Type: text/plain; charset=UTF-8; format=flowed >> >> 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 >> > > No virus found in this outgoing message. > Checked by AVG. > Version: 7.5.552 / Virus Database: 270.10.15/1921 - Release Date: 1/28/2009 > 6:37 AM > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > >