Archived posting to the Leica Users Group, 2007/10/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Gene, I've only got the Hoya filter. I really need to get a 60mm so I may order a B+W and a step up ring 46 to 60. I'm not sure but I think George may be using a Hoya on his Summicron as well. My son is taking his 28mm Summicron back to Boston so I can't do any further testing until Thanksgiving when he returns. I'm glad to hear the new 28 Elmarit asph is fine though. I love that focal length for IR and the M8. Len On Oct 13, 2007, at 8:59 PM, grduprey@mchsi.com wrote: > Len, > > Have you tried a different brand of IR filter? Don't have the > summicron, but my 28 Elmarit Asph does not show this. I have the > Heliopan ir filter on it. Don't know if changing the filter will > make any difference, but worth a try. > > gene > > -------------- Original message from Leonard Taupier > <len-1@comcast.net>: -------------- > > >> George, et al. >> >> I've verified a problem with the 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