James wrote: > Very well put. > But please explain why every AF sigma lens I have doesn't show the correct > apature range on my super A. despite haveing some A contacts. > It's Sigma. > Also why does the MZ60 have only 2 contacts missing when it was never > designed to use A lenses at all. > It's just possible that some "A" information is necessary for the Digital protocol to work and the MZ60 reads what it needs to. Ya think? > Why does the sigma lens when I pulled it apart have all contacts except for > the * go via a flexiable circuit trace to a board in the lens when all that > is required of A contacts is to be shorted or open? > Sigma probably thought it could control which contact was open or shorted dynamically and fool the camera electronics. Which being Sigma they failed miserably at. (Here I'm guessing the first part but I'm sure about the second). > If what you say is true, then the MZ60 should only have the digital pin which > it doesn't. > No, because the digital protocol builds on the A protocol, it needs the information conveyed by the "r" pins, why that choice was made I don't know, but I'm not guessing, I'm thinking. > It is very easy electronicly to make any contact on a F or newer lens to to > have duel function > As I said. only pentax knows what is really going on. every one else > including me is only guessing even Boz. Sorry, it's just bad design. If Pentax was going to double up on a pin's functionality it wouldn't have instituted a separate digital contact. There were plenty of "A" pins already. Pentax made good design decisions up till now, I don't expect them to stop. > When I alerted Boz to the very limited MZ60, even he asked what do the other > contacts do > Maybe Boz was simply telling you to go pound sand. > so far, noone can answer. > Since the MZ60 is only interested in the maximum aperture, (check the chart on the Ka page on Boz's site I'll leave it to you to figure out what the "r" pins and the "m" pins convey, the pattern isn't hard to figure out), I can assume that the digital protocol tells the camera all it needs to know about the minimum aperture and the "m" are superfluous, I say that because it works perfectly well without them. . > James > > On Tue, 06 May 2008 08:04:00 -0400, P. J. Alling wrote: > > So here's the conclusion.
1.) It's cheaper to implement things in software than in hard ware. 2.) Some things necessary for the software to work have to be implemented in hardware. The things necessary were implemented, the rest were deleted to save money, (gee where have we seen that before). >> It's not conjecture that lenses without the pin are identified by Pentax >> DSLRs as A lenses ,and if the pin is blocked the camera shows the same >> behavior. The other connections are simply conductive on non conductive >> spots on the lens mount.on A lenses Even if digital pin simply powers >> the chip the effect is the same, without power the lens becomes "dumb". >> However there's no particular reason to make any of the previously >> existing pins part of the digital communication path and every reason to >> not do that if you care about backward compatibility as it might break >> the "A lens protocol". >> > > > > > -- Vote for Cthulhu. Why settle for a lesser evil... -- Dr. Jerry Pournelle -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
