Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-13-2010, 04:14 AM   #61
Site Supporter
Douglas_of_Sweden's Avatar

Join Date: Apr 2008
Location: Stockholm
Photos: Gallery
Posts: 3,353
I've signed the petition.
There are other good reasons as well, even if my SDM lenses still autofocus.
With SDM there are no converters >1.5x that work. With optional screw drive one could us e1.7x and 2.0x converters on the SDM lenses, and of course 1.5x and 1.4x converters that has only screwdrive and no SDM connection. That leaves more options in term of 3rd party alternatives for us and would enable Pentax to release both a 1.4/1.5x SDM capable converter and a 2.0x screwdrive converter. You could make similar arguments for macro tubes.
SDM appears to take more power from the batteries, so switching to screw drive focus when you don't need to be silent could also be a way to extend battery life.
All these reasons could be used by Pentax to explain why they open up for optional screw drive focus in the firm ware, if they are too shy to admit that people want it to screw drive focus failing SDM lenses.

As many of us have tried, it does not help to cover the SDM contacts. Some of you may remember my thread a year ago where I tried to convert a 2x converter with SDM contacts (aka power zoom contracts) that refused to focus with SDM so that it would focus with the screwdrive gear on a SDM capable body (they of course focus with screw drive on my *istDS).
I took the converter appart and rather than just covering the SDM contacts I removed the SDM contact or the screw drive gear or combinations of the 7 A contacts or the chip in the converter or combinations of these: in conclusion, as soon as the SDM capable camera recognise that it is a SDM lens it prevents the focus engine in the body from working. If you modify the converter enough to hide from the camera that it is a SDM lens, it will believe that it is a A or even K or M lens and will refuse to use any autofocus because such a lens does not have autofocus... For similar resons I don't think you could modify a SDM lens to work with screw drive on a SDM capable body. Pentax reasons may be fear that SDM and screwdrive focus would engage at the same time, but with a menue option where either focus option can be selected, this should be safe.

PS. The same 2x converter is now a very potent SDM macro extension tube. This works because you loose less light with a tube of that ~40mm length than in a 2x converter. But there is no chance I could get the screw drive focus to engage trough that former converter (now tube). DS

01-13-2010, 04:18 AM   #62
New Member
gr8wings's Avatar

Join Date: Feb 2009
Location: Rome (Italy)
Posts: 16
In Italy we can found Tokina 16-50 x Canon and 16-50 Pentax at the same price, about 700 euros.
So the problem is BH, but the price for Tokina is very good.
01-13-2010, 04:54 AM   #63
Pentaxian
Class A's Avatar

Join Date: Aug 2008
Location: Wellington, New Zealand
Posts: 9,193
QuoteOriginally posted by Douglas_of_Sweden Quote
Without weathersealing and SDM for instance (so costs are not the same), and not with Pentax coatings.
The Tokina versions are not wheather-resistant but the Canon version of the 16-50 must have some in-lens motor as well (which is likely to be more reliable than the current SDM, or do Canon users of the Tokina 16-50 report similar trouble?). So this justifies the price difference between $$744.95 (Pentax) and $549 (Tokina) (35.7% extra for the Pentax)? BTW, the comparable Tamron 17-50/2.8 is just $449. I often hear a lot of praise for the latter. Does it miss some "magic" or do Pentax 16-50 buyers value weather-resistance and quick-shift that much?

I often hear people mentioning "Pentax coatings" but do they really mean that much nowadays (as opposed to Pentax prime time when SMC was a real advantage)? Aren't all modern coatings really good and isn't it easy to achieve any colour cast you like in PP? I'm genuinely interested in an answer to this question, it is not a rhetorical question at all.

Last edited by Class A; 01-13-2010 at 05:25 AM.
01-13-2010, 05:00 AM   #64
Pentaxian
Class A's Avatar

Join Date: Aug 2008
Location: Wellington, New Zealand
Posts: 9,193
QuoteOriginally posted by Douglas_of_Sweden Quote
For similar resons I don't think you could modify a SDM lens to work with screw drive on a SDM capable body.
Peter Zack accidentally managed to "modify" one of his K20Ds so that it now drives SDM lenses with the screw drive. So that mode is definitely possible. The respective K20D is not SDM capable anymore actually but in principle the camera is. Hard to imagine how this behaviour was enabled but the software must have a mode for driving SDM lenses with the screw drive.

01-13-2010, 05:03 AM   #65
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,695
According to: Pentax Lenses Explained
DA, D FA, and some FA lenses have an improved "ghost less" coating that is even more effective than the original coating. Furthermore, there are reasons to believe that the SMC coating has been improved from series to series.

Also, SP coating is for dust resistance.
According to: smc Pentax-DA zoom lenses
The Pentax-original SP (Super Protect) coating is applied to the front surface of this lens. Through a vapor deposition process, the lens surface is coated with a special fluorine compound to repel dust, water and grease, making it easy to wipe off fingerprints and cosmetics.

Of course, this is all available knowledge which you may already know and I'm just wasting your time with...
Who knows whether real-world photos show any significant difference with these coatings...
01-13-2010, 05:28 AM   #66
Pentaxian
Class A's Avatar

Join Date: Aug 2008
Location: Wellington, New Zealand
Posts: 9,193
QuoteOriginally posted by Ash Quote
Of course, this is all available knowledge which you may already know and I'm just wasting your time with...
You are never wasting my time, Ash.
I might be wrong but I'm assuming that other manufacturer have very similar features associated with their coatings.

QuoteOriginally posted by Ash Quote
Who knows whether real-world photos show any significant difference with these coatings...
Good question. Until I know the answer, I won't attribute any advantage to Pentax coatings over any other modern coating.
01-14-2010, 01:54 AM   #67
Site Supporter
Douglas_of_Sweden's Avatar

Join Date: Apr 2008
Location: Stockholm
Photos: Gallery
Posts: 3,353
QuoteOriginally posted by Class A Quote
The Tokina versions are not wheather-resistant but the Canon version of the 16-50 must have some in-lens motor as well (which is likely to be more reliable than the current SDM, or do Canon users of the Tokina 16-50 report similar trouble?).

The Tokina version of the 16-50 and 50-135 for Nikon does not autofocus on the Nikon D40, a camera without screw drive focus, so that lens has no built in focus engines. The Canon versions have micro motors that photozone describe as fairly fast but with a squeaky sound.

I recall at least one posting at some other forum where Canon owners discussed if the mechanics of the focus on the 16-50 had got stuck due to dirt. It sounded a bit similar to what people have described for the Pentax version. I have no idea if this is common. I only accidentially read Canon forum (and I'm sorry I can't find it right now), but to know how common common is, one would need to know also how much Tokina have been selling these lenses.


I often hear people mentioning "Pentax coatings" but do they really mean that much nowadays (as opposed to Pentax prime time when SMC was a real advantage)? Aren't all modern coatings really good and isn't it easy to achieve any colour cast you like in PP? I'm genuinely interested in an answer to this question, it is not a rhetorical question at all.
I like to believe that the company that got a head start on coatings may still be ahead of the competition, just as the other company that got a head start on ultrasonic autofocus engines still is ahead of the other brands. But I don't have any proof. Maybe it is just the glimmer of the golden age. It would certainly be interresting to place a high grade spectrometer behind comparable lenses of different brands.

If coatings matter? Yes, I think so. Maybe not so that you can distinguish it with the unaided eye...until...well, if you are into a bit older lenses like I am, you have probably also discovered that you can run into lenses that are not necessarily so old, last bad case I saw was only 10 years old, where the owner managed to rub of a good deal of the coating when cleaning the lens. Then all of a sudden you have a lens that may not be better than an uncoated or single layer coated lens. One thing with the original Pentax Super MC was supposedly that it was more durable, and Pentax claims that their most recent improvements have increased this durability. Sounds nice, doesn't it. Feel free to test if you can rub it off your DA* lens

If I am to make a guess, I would think that Canon and Nikon with their resources should have caught up with the SMC nowadays. But Tokina aint Canikon. They are a rather small company with a tiny research department, often forced to buy into others research as they done with this bunch of Pentax lenses. But the coating of the Tokina 16-50 that I saw had a different color cast than my DA*16-50, so I don't think the coating recepie was included in the deal.
01-14-2010, 01:59 AM   #68
Site Supporter
Douglas_of_Sweden's Avatar

Join Date: Apr 2008
Location: Stockholm
Photos: Gallery
Posts: 3,353
QuoteOriginally posted by Class A Quote
Peter Zack accidentally managed to "modify" one of his K20Ds so that it now drives SDM lenses with the screw drive. So that mode is definitely possible. The respective K20D is not SDM capable anymore actually but in principle the camera is. Hard to imagine how this behaviour was enabled but the software must have a mode for driving SDM lenses with the screw drive.
That's interresting! I'm fairly sure from my experiments that there is no modification on the lens side that can do this (except maybe replacing the chip, but whom of us will be making their own chips at home?). For some reason I never tried to modify the camera (I wonder why). I don't suppose he can tell us how to do it...you call it accidentially...are we talking about a hardware modification (like oops, I dropped the camera in the concrete floor) or did he hack the software somehow?

I'm sure Pentax could do it through the software if they just cared to.

01-14-2010, 03:43 AM   #69
Veteran Member
sterretje's Avatar

Join Date: Dec 2008
Location: Roodepoort, South Africa
Photos: Gallery | Albums
Posts: 3,534
QuoteOriginally posted by Douglas_of_Sweden Quote
That's interresting! I'm fairly sure from my experiments that there is no modification on the lens side that can do this (except maybe replacing the chip, but whom of us will be making their own chips at home?). For some reason I never tried to modify the camera (I wonder why). I don't suppose he can tell us how to do it...you call it accidentially...are we talking about a hardware modification (like oops, I dropped the camera in the concrete floor) or did he hack the software somehow?

I'm sure Pentax could do it through the software if they just cared to.
See https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/85877-i-broke-...t-happier.html
01-21-2010, 04:04 PM   #70
Site Supporter
jpzk's Avatar

Join Date: Jan 2009
Location: Québec
Photos: Gallery | Albums
Posts: 7,255
QuoteOriginally posted by LeDave Quote
That's right... Let's start a fire, instead of complaining and whining in this forum about SDM failures like we all are doing. If we can all get hundreds and if not thousands of forum members to start submitting a request, we could stir things up and maybe have Pentax to actually do something about these SDM lenses. We know that if they can't fix the SDM, we could at least have them release a patch allowing screw-drive focusing.

EDIT: Here is the petition I have just made, thanks flippedgazelle for giving me this idea. Pentax SDM Firmware Petition
Le Dave,

When are you planning to fire this off to Pentax?
Isn't there some sort of big photography show coming up soon?
That would be a good time to shake some "derrières" at Pentax.

JP
03-05-2010, 02:11 PM   #71
Pentaxian
LeDave's Avatar

Join Date: Jun 2009
Location: Minneapolis - St. Paul
Photos: Gallery
Posts: 2,904
Original Poster
My attempt at Live Chat support. As soon as I mention the SDM problems, he decided to end it out lol. I forgot to copy the entire chat, so I'll write down the conversation as I remembered it. This isn't the exact conversation but it is almost exact.

QuoteQuote:
You have been connected with Randall S.

Randall: Hi how can I help you?

Me: The DA* 16-50 and 50-135, as well as several other Pentax DA* lenses have a screw-drive in them, however you are unable to use them on the K-7. Why is that?

Randall: Because that's how the K-7 was made.

Me: Is it possible for a future firmware update allowing the K-7 to use screw-drive?

Randall: Why would you want to use anything other than SDM?

Me: Well, I'm just wondering because they have a screw-drive so why put it there in the first place when you can't even use it.

Randall: It's for older Pentax cameras that are unable to use SDM.

Me: Have you ever owned a Pentax camera?

Randall: Yes, I've used all of them.

Me: Have you ever owned a SDM lens?

Randall: Yes I always use the DA* 16-50 on the K20D.

Me: Have you ever heard of the Pentax SDM Firmware Petition?

Randall: I'm not aware of it.

Me: *Sends link to SDM petition signatures and the screw-drive/SDM poll on Pentax Forums*

--- 2 minutes later ---

Randall: Okay, thanks.

Me: How long have you had your DA* 16-50?

Randall: Do you need help with any other questions?

Me: lol

Chat session ends.

Last edited by LeDave; 03-05-2010 at 02:19 PM.
03-05-2010, 06:42 PM   #72
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,695
Ignorance is bliss until it bites you on the back side...

I've had several discussions with the same Randall which have ended in similar style.
MY SDM petition remains to improve the technology to the point where indeed no-one would ever want to switch back to screwdrive AF - but this is no good to existing SDM lens owners...
03-05-2010, 06:48 PM   #73
Damn Brit
Guest




QuoteOriginally posted by LeDave Quote
My attempt at Live Chat support. As soon as I mention the SDM problems, he decided to end it out lol. I forgot to copy the entire chat, so I'll write down the conversation as I remembered it. This isn't the exact conversation but it is almost exact.
Another resounding public relations success for Pentax. John Carlson must be personally in charge of training the customer support people now.
03-05-2010, 07:26 PM   #74
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 9,535
QuoteOriginally posted by Ash Quote
Ignorance is bliss until it bites you on the back side...

I've had several discussions with the same Randall which have ended in similar style.
MY SDM petition remains to improve the technology to the point where indeed no-one would ever want to switch back to screwdrive AF - but this is no good to existing SDM lens owners...
I did manage to get my DA*50-135/2.8 lens repaired by Pentax Canada, under warranty, but I expect the SDM to blow again in two years or so, at which time I will have to make the decision among a short list of options:
  • Use the lens for the superb optics it is, as a manual focus lens
  • Revert my K10d to firmware 1.20, and use only screw drive
  • Repair the lens for several hundred dollars
  • Replace the lens with something that works.
None of the above options are really palatable. While my K10d has been a fine workhorse for me, the K-7 and its successors are even better, but using them will not allow reversion to use the screw drive. The K10d will not last as long as the film KX, electronic gadgets being what they are, and I will face the decision in a few years.

I have signed the petition. Let us hope that Pentax/Hoya can see their way to getting something for us.
03-11-2010, 11:54 AM   #75
nah
Senior Member




Join Date: May 2008
Location: New Westminster, Canada
Photos: Gallery
Posts: 280
I've just signed the petition too and I've just twittered (?) about it too.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
forum, k-mount, pentax, pentax lens, petition, sdm, sdm petition, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
SDM Petition - REMINDER- bc_the_path Pentax SLR Lens Discussion 4 01-14-2010 06:52 PM
New SDM rear TC, SDM only or SDM + screw drive? morfic Pentax SLR Lens Discussion 1 10-01-2008 08:23 AM
Orphan Works Petition nathancombs Photographic Technique 7 06-21-2008 09:59 PM
FPS rate petition for new K20D time-snaps Pentax News and Rumors 49 01-28-2008 11:22 AM
Starting a Petition benjikan Pentax News and Rumors 22 05-24-2007 12:45 AM



All times are GMT -7. The time now is 06:29 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top