Hi Callum, There are probably a number of things at work here. 1) There is an a tendency with any panoramic camera to encounter uneven light because the field of view is so wide that the light can change significantly across it. Eric's suggestion to meter each exposure or portion of the scene is a good one. 2) The convex film plane will produce some light falloff at the edges of an individual exposure because the film is farther away from the pinhole at the edges than at the center. 3) The blending of three images will produce more density in the middle of the negative than at the edges because the center pinhole casts its image over most, but not all, of the images made by the two pinholes on either side. This leaves the edges of a three-pinhole image less dense than the middle of the image. The majority of the image is a double exposure, but at the very edges it is only a single exposure. The singly exposed parts at the edge of the negative will produce a darker area in the print. An example of this is comparing two of the images of mine that Chris put on the www.pinholeblender.com web site. "Source of the Mississippi" used only the two outer pinholes. This shows the coverage of these two apertures. The dark spot in the right part of "From the Mind of Daruma," which used all three pinholes, is where the center exposure fell off. There are a few ways to deal with this. - you can utilize the fall off as part of the image or your style in making images. - you can crop the image to leave the dark areas out or to minimize them (what I do mostly). - you can dodge the edges when printing. - one idea that I've started to experiment with is advancing the film and making essentially a five-pinhole image with the intention of cropping out the sides for the final print. The outer exposures should be the same density and color as the adjacent exposures. This IS an experiment; I haven't had a chance to print one of these yet but the negs look promising.
Hope this helps. Tom Miller > -----Original Message----- > From: pinhole-discussion-admin@p at ??????? > [mailto:pinhole-discussion-admin@p at ???????]On Behalf Of > callum moffat > Sent: Tuesday, September 09, 2003 4:40 AM > To: pinhole-discussion@p at ??????? > Subject: [pinhole-discussion] pinhole blender > > > after purchasing this camera several months ago, i > just managed to take a test shot with it this weekend > > whilst i dont doubt that the camera is capable of some > great results, and that any new gear needs a period of > learning and some crap foto's my early results were a > bit ropey > > i want to use the camera to produce straight > panaoramics and i noticed that the exposure across the > field was uneven > > is this due to naural vingnetting towards the corners? > and should i be making some compensation > > i exposed the film individually through the three > pinholes rather than trying to pull the magnetic > covers all off at one time (i/m a bit of a sausage > finger) > > also can someone remind me of the cameras f number and > focal length plus field of view > > i realise that i could just e mail chris with these > questions but thought id throw it into the big pot > that is the list > > > many thanks > > callum moffat > > edinburgh scotland > > __________________________________ > Do you Yahoo!? > Yahoo! SiteBuilder - Free, easy-to-use web site design software > http://sitebuilder.yahoo.com > > _______________________________________________ > Post to the list as PLAIN TEXT only - no HTML > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??????? > unsubscribe or change your account at > http://www.???????/discussion/ >
