Archived posting to the Leica Users Group, 2011/11/12
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]What Doug suggests plus do it wide open. Bob Bob Adler www.rgaphoto.com Sirisly On Nov 11, 2011, at 5:34 PM, Doug Herr <wildlightphoto at earthlink.net> wrote: > Adam Bridge wrote: > >>>> > One of my favorite lenses is the Leica 100mm APO that lives on my Canon > 1Ds Mk II. Up close it's fabulous, but at infinity all the great sharpness > is gone, there's just not crisp focus. > > Is this a problem with the adapter I'm using to mount it on the EOS' > mount? Or might it be an issue with the lens itself? And how do I tell > which it might be? > <<< > > Since this lens has a hard stop at infinity (unlike some APO lenses that > focus to infinity and beyond) an adapter that's a tiny bit too thick could > keep the lens from reaching true infinity focus. > > I'd try a series of photos under controlled conditions (MLU, tripod, timer > or cable release, no heat waves) at varying distances. If the adapter's > the problem you should see very sharp photos at all distances short of > infinity. If the lens has a problem I'd expect to see a gradual fall-off > of sharpness as the focus distance approaches infinity. Or find someone > nearby with a 100 APO and do some A/B comparisons. > > Doug Herr > Birdman of Sacramento > http://www.wildlightphoto.com > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information