Archived posting to the Leica Users Group, 2007/01/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Coming in late to the discussion I think that you have to take into account the lens focusing wavelengths out to 800nm. A seriously compromised design like the Noctilux just will not be ideal for this set of wavelengths. The candle out image is sharp on the lead candle and the frame in the background is also sharp. So, the blurring of the image in the lit candle image is probably due to a very different focus point for the IR portion of the image. An interesting experiment when I get my M8 will be to do the old IR twist; focus about one aperture setting closer. ( Move the point of focus to the next aperture mark on the lens from the one that is the correct focus) Don don.dory@gmail.com On 1/7/07, Brian Reid <reid@mejac.palo-alto.ca.us> wrote: > > I wanted to look into the suggestion that the strangeness of M8s and > candles had something to do with focus. > > So I put my M8 on a tripod, set it at ISO640, mounted the Noctilux at > f/5.6, and focused on the wick of the oil candle at the right of this > image: > > http://reid.org/~brian/images/candle3a.jpg 1/20 f/5.6 ISO640 > > I then extinguished the two candles, turned the room lights on, and > increased the shutter speed a little: > > http://reid.org/~brian/images/candle3a.jpg 1/45 f/5.6 ISO640 > > The camera didn't move on the tripod between those two exposures. I'm > fascinated by the purple haze around the oil candle. > > Brian Reid > grateful to all of you who contributed towards my getting this wonderful > camera > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >