Re: contacts. was AF lenses on AF 1.7X adapter
On Wed, 07 May 2008 11:51:47 -0400, P. J. Alling wrote: >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. cannot argue there. I have an older sigma AF lens that works ok on my MZ7 but won't at all on my K10D and MZ60 and the super A gives Apature readings outside the range the lens has. So now it is a single camera use lens. >> 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? personally. No. >> 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). Tracing the circuit in the lens is very hard and for my older eyes, twice as much. Couldn't get very far with this part. >> 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. I also think the R pins are used for digital comunations as well. It is very easy to add extra functions to pins on both sides (camera and lens) for the F protocal while retaining backward compatiability. (except for sigma) Incendently. My DA*16-50 lens has an extra full contact on it's metal mount compared to all other lenses I have. Looks like Pentax have added an extra function to one of the 'm' pins. maybe for SDM. >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. Maybe Pentax added the extra one for some engineering reason. Also depends on what type of serial protocal they used >> 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. He also asked the same of someone else, I can only assume some guy who has provided some tech info for boz >> 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. . Ithink all pins are used in some form of digital protocol. why get only one aperture value digitally when all of it can be done at the same time. I have tried to measure what is happening with my digital multi meter set to logic level. ie logic probe. All I got from all pins was pulsing. ie all went high low high low very quickly. none were stuck high or low Even the digital pin which I think is power. maybe pentax only powers the lens when the camera wants info from the lens thus saving battery power ? If I had a 10 input logic analyser, I would be able to say for sure what is happening. James -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: contacts. was AF lenses on AF 1.7X adapter
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 PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: contacts. was AF lenses on AF 1.7X adapter
James wrote: > 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? Of all your questions, that's the easiest to answer: They do it this way so they can use the same lens mount configuration in all their Pentax-mount lenses and make the shorted/open differences on the main circuit board where all the other Pentax-specific stuff is. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: contacts. was AF lenses on AF 1.7X adapter
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. Also why does the MZ60 have only 2 contacts missing when it was never designed to use A lenses at all. 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? If what you say is true, then the MZ60 should only have the digital pin which it doesn't. 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. When I alerted Boz to the very limited MZ60, even he asked what do the other contacts do. so far, noone can answer. James On Tue, 06 May 2008 08:04:00 -0400, P. J. Alling wrote: >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". -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: contacts. was AF lenses on AF 1.7X adapter
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". James wrote: > On Mon, 05 May 2008 14:27:04 -0400, P. J. Alling wrote: > > In my mind, there is a lot of conjecture about the "digital" pin. > I believe that it is power for the lens chip. > Noone knows what is really going on with all the contacts except pentax. > Sigma have reversed enginered the contacts and maybe tamron got the info from > pentax. > > James > > > > >> Just a follow up on my earlier serious answer. The 1.7x AF Adapter >> lacks the digital data pin, (seen here >> at Boz's K >> mount technical page), on it's female mount. Without that pin there can >> be no communication between the lens and camera, so the camera has no >> ability to treat the lens as anything other than an "A" lens. >> > > > > > > > > -- Vote for Cthulhu. Why settle for a lesser evil... -- Dr. Jerry Pournelle -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: contacts. was AF lenses on AF 1.7X adapter
On Mon, 05 May 2008 14:27:04 -0400, P. J. Alling wrote: In my mind, there is a lot of conjecture about the "digital" pin. I believe that it is power for the lens chip. Noone knows what is really going on with all the contacts except pentax. Sigma have reversed enginered the contacts and maybe tamron got the info from pentax. James >Just a follow up on my earlier serious answer. The 1.7x AF Adapter >lacks the digital data pin, (seen here > at Boz's K >mount technical page), on it's female mount. Without that pin there can >be no communication between the lens and camera, so the camera has no >ability to treat the lens as anything other than an "A" lens. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
