Archived posting to the Leica Users Group, 2007/10/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I forgot I had the proper Cokin adapters and 89B IR filter for the 28mm Summicron. With that setup the hot spot is still there. So the problem is not dependent on the brand filter. Jim, I'll still look into the Opteka brand. The Cokin is cumbersome to use in the field. Len On Oct 13, 2007, at 11:19 PM, Jim Hemenway wrote: > Gents: > > I've had very good luck with the R72 Opteka brand filters from 47th > Street Photo in NY. Much better prices than Hoya. > > Check ebay item number 280159299554 for an example. > > Just received my 58 and 67mm filters today and have previously > purchesed both a 49 and a 77mm filter from them. Seem to be good > quality to me. > > Jim > > Leonard Taupier wrote: > >> 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 >> _______________________________________________ >> 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