Archived posting to the Leica Users Group, 2010/09/11
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Well silicone (the polymer) contains silicon (our metalloid chemical friend) and we knew exactly what you were helpfully discussing, Franke! Besides I can think of some silicone applications that REALLY would not work well if made only from silicon. Ask Pamela Anderson. Cheers Geoff http://www.pbase.com/hoppyman NO ARCHIVE On 11 September 2010 20:02, FRANK DERNIE <frank.dernie at btinternet.com>wrote: > More crap spelling than wandering mind I fear... > > > ----- Original Message ---- > From: "piers at hemy.org" <piers.hemy at gmail.com> > To: Leica Users Group <lug at leica-users.org> > Sent: Saturday, 11 September, 2010 9:37:52 > Subject: Re: [Leica] not sure - but here goes > > Spot on, Frank, of course. But you mean silicon - perhaps your mind > was wandering? > > On 9/11/10, Frank Dernie <Frank.Dernie at btinternet.com> wrote: > > Hi Mark, > > on the off chance your question is not rhetorical here are a few reasons > for > > the difference in price between small and large sensors being much bigger > > than thet between 35mm and 120 film. > > Firstly the film is the same stuff, just a different shaped layer of > plastic > > coated with the same light sensitive stuff. > > In the case of sensors they are made on a wafer of silicone. The crystal > > structure of the silicone wafer has imperfections on it, and any chip > etched > > onto a part of the silicone wafer with an imperfection won't work, so it > is > > scrap. If, for example there is a defect every 2 inches, -all- 2 inch or > > bigger chips will be scrap, so that is the biggest sensor which can be > made > > will be less than 2". Depending on how the layout of random faults and > the > > sensor layout fall on a wafer, there will be a high scrap rate even on > > sensors less than 2". The scrap rate only comes down to negligible when > the > > sensors are -very- much less than 2". > > This means big sensors are expensive since very few few of those produced > > work. They are also expensive since the economy of scale is not there. > Some > > are made by joining 2 smaller sensors together with software to "fix" the > > image at the join... > > The technology for making the wafers is developing, so prices will come > down > > eventually, but never to the film ratio. > > > > Luckily, the sensor design of small and big chips is -not- the same, > unlike > > film. With film, going larger format increases the potential quality by > the > > increase in film area less the reduction in lens quality due to the > larger > > image circle. Going smaller with digital the loss is -much- less than > with > > film since the smaller sensors are -much- finer resolution than large > > sensors so the loss of quality is not nearly as much as it used to be > with > > film. > > cheers, > > Frank > > > > On 11 Sep, 2010, at 07:12, Mark Rabiner wrote: > > > >> Brownie film does not cost that much more than 35mm film. Why should > >> digital? Well it does. Bummer. > > > > > > _______________________________________________ > > 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 >