Chet's images was taken with a 15mm. That wide it seems unlikely that such vibrations could have any impact.
It pretty much rule out the thermal distortions suggestions too. There are plenty of other images on the Net showing the same effect also. Found it also in one of my own recent images from Newcastle: http://oksne.net/foto/html/essays/PDML_UK_III/essay.asp in the picture of the rebuilt Roman gatehouse. The brick pattern is far too visible. Many of the images from the night photo group "The Nocturnes" also show the same, but only in their colour photos. http://www.thenocturnes.com/gallery.htm Loss of acutance seem to be the most resembling technical description to the phenomenon, imo. A google search for "acutance" brings up a lot of links, of which many describe b/W developer properties. It seems that there is a lot of awareness of this issue among b/w darkroom enthusiasts. For colour films, however, I have found next to nothing on this issue. Interesting subject, though. Almost demands some experiments... :-) Jostein ----- Original Message ----- From: "Dan Scott" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: "Dan Scott" <[EMAIL PROTECTED]> Sent: Thursday, November 21, 2002 5:31 AM Subject: Re: Night photography > > On Tuesday, November 19, 2002, at 02:22 PM, Jostein wrote: > > > There were so many interesting thoughts in the Moonlight-thread as to > > why the images _seemed_ blurred; > > > > - film reciprocity failure, > > - lower film accutance, > > - motion blur (leaves), > > - camera shake, > > - focusing problems, > > - thermal distortions in the air... > > > > Has earth vibration transmitted through the tripod been ruled out? The > ground tembles all the time, doesn't it? Are people moving around doing > things near the tripod while the exposure is taken? Nearby roads or > freeways? Is the tripod lacking sufficient weight to resist small > vibrations? Is there any play between lens and body or the body and the > tripod head that could accentuate minute vibrations transmitted > throught the tripod? > > Dan Scott > >
