K AND M LENSES always have the same functionality and didnt ever need stop down metering until Pentax removed the aperture cam sensors from their K mount bodies when they went to digitial SLRS to save money and/or promote new lens sales. jco
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Frits Wüthrich Sent: Sunday, June 24, 2007 5:24 PM To: [email protected] Subject: Re: what's the difference between M and A? Don't know about K lenses, but the M lenses I had, the 50, 135 and 200 mm didn't need stop down metering on my MX camera's, or the ME or ME super. On Sunday 24 June 2007 22:17, mike wilson wrote: > Vic Mortelmans wrote: > > Hi, > > > > OK, obviously I do know that A-lenses have an A-modus, allowing the > > camera to set the aperture (shutter-priority modes), while M-lenses > > always require the aperture to be set on the lens. > > > > But being in persuit of a 50mm f/1.4, I notice that the A-model is > > priced at least twice as high as the M-model, if not more. > > > > Looking at the mechanics of the diaphragma, I wonder if an A-lens is > > that different, apart from the electronic contact that probably > > doesn't do anything more than telling the camera whether the A-mode > > is on or off. > > > > And I also assume that the 50mm f/1.4 M and A are optically > > identical? > > > > So is there any objective reason for the price difference, or is it > > just the game of demand and available quantity that sets the price? > > You got the reason in the first paragraph. M and K lenses need the > non-standard use system of pressing a button to take a stopdown > exposure reading before each shot. A lenses seem to have more plastic > parts in them and are alleged to be not built as well as previous > series. -- Frits Wüthrich -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
