Archived posting to the Leica Users Group, 2005/01/15
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]on 1/15/05 5:51 PM, joe weil at weiljr@earthlink.net wrote: > Hello, > I am hoping that greater knowledge of this group will give me some insight > to what I noticed on my negatives (Tri-X, shot at 400). I was shooting at > night with an R-8 and an older Summicron R 90 (Canada, # 2,463,XXX). In the > negatives shot with this lens, I noticed a secondary image of a bright > light source (a streetlight) in the negative as well. The street light was > positioned in the lower right hand corner of the negative and the secondary > reflection was located in the upper left corner so it seems to be symetric > about both the x and y axis. The secondary reflection was obviously > stronger as exposure time was increased. I spot metered off the street > light, opened up 2 stops and bracketed a couple stops in both directions. I > believe the aperture was somewhere between 2 and 4 and was constant when > the exposures were taken. There was a Hoya 81A filter in front of the lens > during the exposures. > I checked the lens and filter to see if they were clean and there was > nothing obvious on either. > > What would cause this secondary reflection, the lens, the filter or both? > Has anyone else experienced this phenomena? > I am planning an experiment to shoot with this lens at night with a single > bright light source at a small, medium and large aperture, with and without > the filter. Metering would be performed the same as I did above with an > obvious slant toward overexposure. > If you have any other ideas of things that I could try to figure it out, > please let me know. > Thanks > Joe > Take the filter off. Doug Herr Birdman of Sacramento http://www.wildlightphoto.com