Re: DA 16-50 lens with faulty SDM?
Resend: (probably obsolete by now but I am happy I can finally post) > Had the same thing on my K10D with a ten week old 16-50 bought from a > gentleman who claims he used it twice before having to put it up for sale to > raise funds for his house payments. Shaft drive wouldn't work either, > playing with AF/MF on lens and body didn't have any impact either. > > Took it to Pentax Germany (lucky to live nearby), cross tested with another > 16-50 and a K20D and left it there for repair. Got a letter a few days later > from Maerz, the new outsourced repair place saying it would take longer, the > SDM control chip had bought it and the spare part wasn't in stock. As time > ran out, I finally contacted Pentax again, told them of an upcoming wedding > (just a friend's, I don't shoot them for a living) and they ended up giving > me a new lens. > > So now that I have the lens, I like it a lot, I don't find AF overwhelmingly > quick but it hunts much less than my other lenses and I appreciate both how > quiet the AF is and how little mirror/shutter noise gets past the weather > sealing; it makes shooting much more quiet than with any of my other glass. > On the downside, there is visible distortion at 16mm and images are soft > throughout the aperture range to a point where it has me thinking about > going back to Pentax for another copy... > > Cheers > Ecke -- 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: DA 16-50 lens with faulty SDM?
On Sat, Aug 22, 2009 at 6:44 PM, Joseph Tainter wrote: > Until Pentax get these problems fixed, I won't buy any more SDM lenses. Hoya > has dramatically increased the price of lenses while refusing to improve > manufacturing quality. > > Joe My limited readings on the subject point to a Dual AF problem, not an SDM problem per se. It doesn't change the problem at all but it means SDM-only lenses have much less problem if at all. I remember a Pentax rep stating that future lenses would be either screwdriven or SDM driven but not both as it posed manufacturing and reliability problems. -- Thibault Massart aka Thibouille -- Photo: K10D,Z1,SuperA,KX,MX, P30t and KR-10x ;) ... Thinkpad: X23+UB,X60+UB Programing: D7 user (trying out D2007) -- 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: DA 16-50 lens with faulty SDM?
Oh, I knew to look out for that, (un)fortunately I won't have to with this lens. What did you replace your 50-135 with (if you did)? On Sat, Aug 22, 2009 at 9:44 AM, Joseph Tainter wrote: > Yes, the SDM is faulty. If you get another copy of the lens, check carefully > for element misalighment, indicated by edge softness at the right side. Oh, > and some copies have it at the left side. > > There have been many, many requests to Pentax to give us a firmware option > to use either SDM or shaft drive on DA* lenses that have both. Pentax > refuses to do this, and they will not acknowledge that there is a problem. > When SDM fails you may be able to focus manually. When the SDM on my (second > of three) DA* 50-135 failed in Rome last November, I couldn't even turn the > focus ring manually. > > Until Pentax get these problems fixed, I won't buy any more SDM lenses. Hoya > has dramatically increased the price of lenses while refusing to improve > manufacturing quality. > > Joe -- 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: DA 16-50 lens with faulty SDM?
You know that just might work if the existence of power contacts on the lens is what tells the camera it's a SDM lens. However I suspect it's actually querying the lens through the digital information contact. It's shown on the figure on this page. http://www.bdimitrov.de/kmp/technology/K-mount/Kaf.html I don't think blocking the power contacts will help, and anything you might block them with is likely to be sticky, I wouldn't be too sanguine about putting something sticky, that might come loose, in the mirror box of my SLR. gldnbearz wrote: Is there a way to block the SDM contacts for an over-ride? - Pat On Sat, Aug 22, 2009 at 6:11 AM, P. J. Alling wrote: Obviously not. If the chip in the lens tells the camera it's an SDM lens, then by GOD that's what we'll use to focus. It's simple minded programing, lots of state checking tends to slow things down when everything is working right. It doesn't surprise me that there is no fall back to a "less advanced" auto focus mode, even if the camera has been programed to notice the failure at all. -- 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. -- The free man owns himself. He can damage himself with either eating or drinking; he can ruin himself with gambling. If he does he is certainly a damn fool, and he might possibly be a damned soul; but if he may not, he is not a free man any more than a dog. --G. K. Chesterton -- 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: DA 16-50 lens with faulty SDM?
On Aug 22, 2009, at 17:29 , gldnbearz wrote: Is there a way to block the SDM contacts for an over-ride? All the digital data between the camera and the lens uses one single pin. If you block that pin, you will have an unknown manual lens. The other pins (and an illustration) are explained on Boz's site. Text from that page: The KA mount requires body-lens communication that cannot be accomplished via the mechanical couplings of the original K-mount. First, in order to know when to use the Tv or P operating mode, the body needs to be able to determine if the lens aperture ring is set to "A". Second, after the body measures the scene's brightness and determines how many stops the lens should be closed, it must know if the lens can be closed that many stops. Finally, in the Tv and P operating modes, the higher-end KA bodies display the picture-taking f- stop in the viewfinder. In order to support this feature, the body needs to know the absolute value of the lens widest f-stop. Pentax implemented all of the above functionality by adding six electrical contacts to the flat surface of the body and lens mounts. These contacts are located in different positions from those of the KF mount, and therefore do not lead to any incompatibilities. On the body mount, the "*" contact is slightly recessed. On the lens mount, "*" is a small pin whose head can be raised or lowered depending on the position of the lens aperture ring. When a numeric f- stop is selected, the pin's head is lowered so that it does not make contact with body's "*" contact; when the "A" aperture setting is engaged, the pin's head is raised, and it makes electrical contact with the body's "*" contact. The remaining five contacts are easily seen on the body. They look like small, slightly-protruding, ball-bearings. The lens-mount contacts are of two types: conducting and non-conducting. The non- conducting contacts are small plastic circles. The conducting contacts usually cannot be seen, because it is the (metal, and thus conducting) mount that fulfills their role. In rare cases, the lens mount has five holes, some of which are filled with plastic, and some with a golden metal. The golden metal and the plain "mount" contacts seem to have identical functionality. Inquiring Minds Want to Know The conducting/non-conducting pattern that the lens contacts form is decoded by the body as the lens' narrowest aperture and number of f- stops. George de Fockert deciphered the pattern by cycling through all possible combinations on a ProgramA in program mode and looking at the minimum and maximum apertures shown in the viewfinder. The table below shows the lens contact patterns in the following order r1r2m1*m2r3 where each contact is either metal (represented by 1) or plastic (represented by 0). The page: http://www.bdimitrov.de/kmp/technology/K-mount/Ka.html Joseph McAllister pentax...@mac.com “ It is still true, as was first said many years ago, that people are the only sophisticated computing devices that can be made at low cost by unskilled workers!” — Martin G. Wolf, PhD -- 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: DA 16-50 lens with faulty SDM?
Is there a way to block the SDM contacts for an over-ride? - Pat On Sat, Aug 22, 2009 at 6:11 AM, P. J. Alling wrote: > Obviously not. If the chip in the lens tells the camera it's an SDM lens, > then by GOD that's what we'll use to focus. It's simple minded programing, > lots of state checking tends to slow things down when everything is working > right. It doesn't surprise me that there is no fall back to a "less > advanced" auto focus mode, even if the camera has been programed to notice > the failure at all. -- 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: DA 16-50 lens with faulty SDM?
Returning the lens is exactly what I intend to do... after I try it out on the *istDS this weekend. Not my intended use for this lens, but B & H customer service is closed on Saturdays and UPS/FedEx doesn't pick up on Sunday. It should give me enough info to see if I can live with its size and weight. OTOH, now knowing that the SDM is prone to failure, perhaps all the more reason to stick with my so-far faultless DA 16-45. I don't intend to spend this type of money on an manual focus lens for my K200D. - Pat On Sat, Aug 22, 2009 at 10:17 AM, Carlos Royo wrote: > I have a DA 50-135 which has developed exactly the same problem, namely: > screwdriver focusing works on an *ist DS, but SDM doesn't (on a K10D GP). > You should return that lens. > > Carlos -- 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: DA 16-50 lens with faulty SDM?
gldnbearz escribió: I purchased a used DA 16-50 from B&H, rated at 9+. I put the lens on my K200D and immediately realize that the lens won't auto focus. I check the AF/MF switches on both the camera body & lens to make sure that all was in the AF position (or rather, none was in the MF position). I can manually focus the lens without problems. I have also cleaned the SDM contacts on the lens, without any success. Camera focuses fine with the DA 50-135 lens, so I doubt it is a problem with the SDM on the body. OTOH, when I place the lens on the *istDS, the lens will auto focus. I'm guessing that the SDM component on the lens has failed. If that is the case, will it not revert to the standard screw drive on a body that has SDM ability? I have a DA 50-135 which has developed exactly the same problem, namely: screwdriver focusing works on an *ist DS, but SDM doesn't (on a K10D GP). You should return that lens. Carlos -- 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: DA 16-50 lens with faulty SDM?
Pat wrote: I purchased a used DA 16-50 from B&H, rated at 9+. I put the lens on my K200D and immediately realize that the lens won't auto focus OTOH, when I place the lens on the *istDS, the lens will auto focus. I'm guessing that the SDM component on the lens has failed. If that is the case, will it not revert to the standard screw drive on a body that has SDM ability? _ Yes, the SDM is faulty. If you get another copy of the lens, check carefully for element misalighment, indicated by edge softness at the right side. Oh, and some copies have it at the left side. There have been many, many requests to Pentax to give us a firmware option to use either SDM or shaft drive on DA* lenses that have both. Pentax refuses to do this, and they will not acknowledge that there is a problem. When SDM fails you may be able to focus manually. When the SDM on my (second of three) DA* 50-135 failed in Rome last November, I couldn't even turn the focus ring manually. Until Pentax get these problems fixed, I won't buy any more SDM lenses. Hoya has dramatically increased the price of lenses while refusing to improve manufacturing quality. Joe -- 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: DA 16-50 lens with faulty SDM?
Obviously not. If the chip in the lens tells the camera it's an SDM lens, then by GOD that's what we'll use to focus. It's simple minded programing, lots of state checking tends to slow things down when everything is working right. It doesn't surprise me that there is no fall back to a "less advanced" auto focus mode, even if the camera has been programed to notice the failure at all. gldnbearz wrote: I purchased a used DA 16-50 from B&H, rated at 9+. I put the lens on my K200D and immediately realize that the lens won't auto focus. I check the AF/MF switches on both the camera body & lens to make sure that all was in the AF position (or rather, none was in the MF position). I can manually focus the lens without problems. I have also cleaned the SDM contacts on the lens, without any success. Camera focuses fine with the DA 50-135 lens, so I doubt it is a problem with the SDM on the body. OTOH, when I place the lens on the *istDS, the lens will auto focus. I'm guessing that the SDM component on the lens has failed. If that is the case, will it not revert to the standard screw drive on a body that has SDM ability? Looks like I will be boxing this lens back up to send back to B&H. What a poopy way to start the weekend. =( - Pat -- 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. -- The free man owns himself. He can damage himself with either eating or drinking; he can ruin himself with gambling. If he does he is certainly a damn fool, and he might possibly be a damned soul; but if he may not, he is not a free man any more than a dog. --G. K. Chesterton -- 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.
DA 16-50 lens with faulty SDM?
I purchased a used DA 16-50 from B&H, rated at 9+. I put the lens on my K200D and immediately realize that the lens won't auto focus. I check the AF/MF switches on both the camera body & lens to make sure that all was in the AF position (or rather, none was in the MF position). I can manually focus the lens without problems. I have also cleaned the SDM contacts on the lens, without any success. Camera focuses fine with the DA 50-135 lens, so I doubt it is a problem with the SDM on the body. OTOH, when I place the lens on the *istDS, the lens will auto focus. I'm guessing that the SDM component on the lens has failed. If that is the case, will it not revert to the standard screw drive on a body that has SDM ability? Looks like I will be boxing this lens back up to send back to B&H. What a poopy way to start the weekend. =( - Pat -- 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.
