On 21 Jun 2002 at 19:39, Bob Rapp wrote: > P�l, > While this was the original intent, linearising the response of the > meter is important in all photography. All that is needed is to check the > response of the various photo diodes on the market. The beauty of the old > CDS and selenium meters is that they have a broad range on sensitivity. > > Bob(not wanting to start an argument)
Hi Bob, Not wanting to perpetuate an argument but I do recall from my younger days playing with CdS cells in a variety of home brewed circuits that they have a very limited spectral response which is centred about the green area of the spectrum much like the human eye. They also have a slow response time, are less linear then SBC and their sensitivity decreases over time (even if encapsulated in a hermetically sealed environment) Check the following pages for reference: http://www.ecs.soton.ac.uk/publications/rj/1994/transduc/ross/ross.html http://www.plazaearth.com/usr/gasperi/cds.htm Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
