Precisely. I had to write off an A 1:1.7 50mm because of a problem with the little springs that control the A setting button. These parts don't exist on the ringless lenses.
Fortunately a nice man from Newcastle took it off my hands..... John On Sat, 19 Aug 2006 04:45:42 +0100, Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: > > On Aug 18, 2006, at 6:39 PM, Digital Image Studio wrote: > >> On 19/08/06, Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: >> >>> A lens without an aperture ring is less likely to break no matter >>> what you choose to do with it: it has fewer parts to break. >> >> Huh? It just doesn't have an aperture ring, the aperture isn't set by >> magic otherwise. > > In a lens without an aperture ring, or in a lens with the aperture > ring set to A, the lens opening is set by metered action of the > camera's actuation lever on the lens' iris regulator lever. > > Using a lens with an aperture ring set to anything other than A means > a) the communication contacts to the body are open circuit so there > are commutators involved, b) the ring controls a limit stop for the > mechanism internally, the camera actuator simply drops through to its > minimum aperture setting and the iris regulator comes up against the > limit stop set by the ring. There are detent fingers, little springs > operating on notches in the mechanism, the A button and spring for > it, the connection between the ring and the limit stop, etc. > > Yes, a lens without an aperture ring doesn't have an aperture > ring ... and it doesn't have all the parts associated with the > aperture ring either. It just has the iris regulator mechanism to > interact with the camera actuator and a permanently connected set of > contacts to communicate with the body. > > Thus the lens lacking an aperture ring is simpler and likely more > robust on that basis. > > Godfrey > -- Using Opera's revolutionary e-mail client: http://www.opera.com/m2/ -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
