Archived posting to the Leica Users Group, 2007/10/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Mine seems to be free of this problem. Nice even alumination over the entrie field. It has higher contrast when compared to the Summicron though, or so I have been told. Gene -------------- Original message from Leonard Taupier <len-1@comcast.net>: -------------- > Steve, > > So far that's two for two. (George's and my son's). I had to borrow > my sons as I only have the Elmarit. It would be interesting to know > how the new Elmarit asph fares. > > Len > > > On Oct 12, 2007, at 5:11 PM, Steve Barbour wrote: > > > > > On Oct 12, 2007, at 2:10 PM, Leonard Taupier wrote: > > > >> George, et al. > >> > >> I've verified a problem with the > > > > (or my) ?? > > > > > > ....tested one sample, or multiple cron 28's....? > > > > > > > >> 28mm Summicron on an M8 and IR filter when trying to take Infra > >> Red photos. > >> > >> There is a hot spot present in the center of the frame when trying > >> to take IR photos with the above setup. The problem looks like > >> flare, a circle of low contrast in the center of the frame. The > >> problem is most noticeable at the smaller lens openings where the > >> hot spot is clearly defined. As the lens is opened up the hot spot > >> becomes larger and less pronounced but the center area is still > >> lower contrast. I did not see this at f2 and f2.8. Here is a photo > >> taken at f16. > >> > >> > >> 28mmSummicronIR.jpg.html> > >> or > >> http://tinyurl.com/yreo78 > >> > >> I used two M8 cameras for the test. All photos were taken on a > >> tripod with the sun directly behind the camera and shaded by my > >> body. The filter was a Hoya R72. A lens hood was on the lens. The > >> problem showed up with both M8 cameras. > >> > >> The same test was also performed using the 28mm f2.8 Elmarit (non- > >> asph), 35mm Summicron asph, 24mm Elmarit asph and the 21mm Elmarit > >> asph. Only the 28mm Summicron asph showed the hot spot problem. > >> > >> The problem does not show up when using a Red R60 filter. > >> > >> Len > >> > >> > >> > >> > >> > >> > >> _______________________________________________ > >> 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