Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-12-2011, 11:00 AM   #91
Veteran Member
gnaztee's Avatar

Join Date: Nov 2007
Location: Cornelius, OR
Posts: 752
QuoteOriginally posted by JHD Quote
New or used, anyone who buys an SDM lens should know the risk they're taking and that failure is highly probable.
That should read "highly possible"

01-12-2011, 11:13 AM   #92
Veteran Member
PentaxPoke's Avatar

Join Date: Jan 2008
Location: Oklahoma
Posts: 1,411
QuoteOriginally posted by gnaztee Quote
That should read "highly possible"
Every SDM lens I owned failed one way or another. All were due to QC problems, and three were due to SDM failure.

I'm just sayin...
01-12-2011, 11:21 AM   #93
Veteran Member
gnaztee's Avatar

Join Date: Nov 2007
Location: Cornelius, OR
Posts: 752
QuoteOriginally posted by PentaxPoke Quote
Every SDM lens I owned failed one way or another. All were due to QC problems, and three were due to SDM failure.

I'm just sayin...
And my SDM lens hasn't failed, and there are numerous web forum posts about SDM lenses that have failed, and numerous posts about SDM lenses that haven't failed, and so...we can conclude that it is possible SDM will fail, but in the absence of hard statistics have no clue whether it's probable SDM will fail.

I'm just sayin' too

Last edited by gnaztee; 01-12-2011 at 11:37 AM. Reason: double word
01-12-2011, 11:35 AM   #94
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
QuoteOriginally posted by gnaztee Quote
And my SDM lens hasn't failed, and there are numerous web forum posts about SDM lenses that have failed, and numerous posts about SDM lenses that haven't failed, and so...we can conclude that that it is possible SDM will fail, but in the absence of hard statistics have no clue whether it's probable SDM will fail.

I'm just sayin' too
Agreed.

No one knows the exact numbers, aside from Pentax themselves, and I doubt they would be forthcoming with the information.

That said, it's hardly "probable" that SDM will fail on a given lens, sugeesting that over the life of a given lens it's got a better than 50% chance of failing. I have 4 SDM lenses and I fully acknowledge that it's possible (maybe even somewhat likely) that at some point one of them will fail. I also have no doubt that it is significantly more probable for an SDM lens to fail compared to a screw-driven lens.

And if someone is risk-adverse, then I would recommend staying away from SDM lenses altogether as the constant wondering "when is my lenses going to die" could potentially take away the enjoyment of the lens while it's not broken. However, for someone who is aware of the potential risk (which, again, is possible, not probable) and who is aware of the consequences of a failure (a $200 repair), there are many fine SDM lenses that are more than worth considering despite the potential for failure.

01-12-2011, 12:20 PM   #95
Veteran Member
sewebster's Avatar

Join Date: Jun 2008
Location: Vancouver, BC
Photos: Gallery
Posts: 533
QuoteOriginally posted by dgaies Quote
That said, it's hardly "probable" that SDM will fail on a given lens, sugeesting that over the life of a given lens it's got a better than 50% chance of failing.
But what is the life of a lens? How about, 40 years? Lots of lenses that old still seem to work. It wouldn't take too much to convince me that it is _probable_ for SDM to fail in that time. However, perhaps that is entirely reasonable and something that people are willing to accept.

While silent in-lens motors (and other electronics such as IS/VR) have advantages, it is one more thing to break and may limit the lifespan of modern lenses. Lenses might not be as much of an "investment" as they once were.
01-12-2011, 12:32 PM   #96
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
QuoteOriginally posted by sewebster Quote
But what is the life of a lens? How about, 40 years? Lots of lenses that old still seem to work. It wouldn't take too much to convince me that it is _probable_ for SDM to fail in that time. However, perhaps that is entirely reasonable and something that people are willing to accept.

While silent in-lens motors (and other electronics such as IS/VR) have advantages, it is one more thing to break and may limit the lifespan of modern lenses. Lenses might not be as much of an "investment" as they once were.
I'll agree with that; over 40 years it most likely is probable that the SDM would fail. There's no question that once you start adding things like motors other electronic components to lenses that the expected life of the lens (without repairing it) gets shortert. But it's the same with other things, like cars and TVs (and lots of other products). As you start adding more features they require more potential repairs down the road to keep them functional. And sometimes, but not always, these repairs are cost prohibitive relative to the replacement cost.

I suppose I should amend my last post to say if you are risk-adverse or want the best chance of having your lens work in 40 years, you should stay away from SDM. On the other hand, if over a long period of time you have to replace the SDM motor every 5 years at a cost of $150-200, there are probably some people (myself included) that would be willing to factor that into the "real cost" of owning the lens and then make my decsion accordingly.
01-12-2011, 01:15 PM   #97
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,951
QuoteOriginally posted by dgaies Quote
I'll agree with that; over 40 years it most likely is probable that the SDM would fail. There's no question that once you start adding things like motors other electronic components to lenses that the expected life of the lens (without repairing it) gets shortert. But it's the same with other things, like cars and TVs (and lots of other products). As you start adding more features they require more potential repairs down the road to keep them functional. And sometimes, but not always, these repairs are cost prohibitive relative to the replacement cost.

I suppose I should amend my last post to say if you are risk-adverse or want the best chance of having your lens work in 40 years, you should stay away from SDM. On the other hand, if over a long period of time you have to replace the SDM motor every 5 years at a cost of $150-200, there are probably some people (myself included) that would be willing to factor that into the "real cost" of owning the lens and then make my decsion accordingly.
Most cars now have power windows. I have had a couple of vehicles where those motors burned out and they are quite expensive to replace. There are all sorts of other places where devices have gotten more complex and therefore more likely to break.

In lens motors do break. This is true for every camera company out there. Particularly with the cheaper end "silent wave" motors, the rate is not infrequent. Unfortunately, to this point I have only heard people who have had SDM motors break say that they all break and those who haven't had problems say that they are reliable.

For those who really want a lens that will "last forever," manual focus is definitely the way to go. Probably look into one of the cheap zeiss lenses that are available new. Probably best not to use it either, since if you drop it there will certainly be no warranty coverage.
01-12-2011, 06:38 PM   #98
Banned




Join Date: Nov 2010
Location: Williston, VT
Posts: 268
QuoteOriginally posted by Rondec Quote
Most cars now have power windows. I have had a couple of vehicles where those motors burned out and they are quite expensive to replace. There are all sorts of other places where devices have gotten more complex and therefore more likely to break.
That's a terrible analogy.

...besides, power window motors last longer than SDM motors.

01-12-2011, 07:01 PM   #99
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,951
QuoteOriginally posted by Hound Tooth Quote
That's a terrible analogy.

...besides, power window motors last longer than SDM motors.
Yes, but since I have experienced power window motors burn out and I can find other people on the internet with similar experiences, clearly the rate of burn out of these motors eventually approaches 100 percent. Not so different from SDM, you see.
01-12-2011, 07:35 PM   #100
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
QuoteOriginally posted by Rondec Quote
Yes, but since I have experienced power window motors burn out and I can find other people on the internet with similar experiences, clearly the rate of burn out of these motors eventually approaches 100 percent. Not so different from SDM, you see.
Ironically, I've had to replace a power window motor in my car once as well.

I can now conclude that if you own a car with power windows and SDM lenses, one of the two will fail, but not both

Last edited by dgaies; 01-12-2011 at 07:51 PM.
01-12-2011, 07:53 PM   #101
JHD
Veteran Member




Join Date: Jan 2010
Photos: Albums
Posts: 1,407
Comparing the reliability of power windows to SDM lenses is laughable. Thanks God Pentax doesn't make power windows!
01-12-2011, 08:06 PM   #102
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
QuoteOriginally posted by JHD Quote
Comparing the reliability of power windows to SDM lenses is laughable. Thanks God Pentax doesn't make power windows!
Nobody is actually comparing the two in terms of reliability. I think we can all agree that power windows are orders of magnitude more reliable than the motor in SDM lenses. However, that was hardly the point of the original analogy, and I am fairly certain you knew that.

I realize you hate SDM lenses and I can only assume that you've had at least one bad experience with them personally. I'm not a Pentax/SDM apologist and would like nothing more than for SDM lenses to be replaced with something more reliable and faster. I think that the move to SDM lenses on Pentax's higher end glass, and their associated QC issues, has done considerable harm to Pentax's sales and reputation.

That said, the notion that people should never buy one because of the possibility that they may fail outside the (short) one year warranty doesn't make sense. I buy lots of things that I fully understand may break and need repair outside it's warranty period (my car being one of those). It just doesn't make sense (to me) to dismiss every single DA* SDM lens because of possibility it may fail and need its motor replaced at some point down the road.
01-12-2011, 08:38 PM   #103
Pentaxian
johnmflores's Avatar

Join Date: Apr 2009
Location: Somerville, NJ
Photos: Gallery | Albums
Posts: 5,004
QuoteOriginally posted by dgaies Quote
Nobody is actually comparing the two in terms of reliability. I think we can all agree that power windows are orders of magnitude more reliable than the motor in SDM lenses. However, that was hardly the point of the original analogy, and I am fairly certain you knew that.

I realize you hate SDM lenses and I can only assume that you've had at least one bad experience with them personally. I'm not a Pentax/SDM apologist and would like nothing more than for SDM lenses to be replaced with something more reliable and faster. I think that the move to SDM lenses on Pentax's higher end glass, and their associated QC issues, has done considerable harm to Pentax's sales and reputation.

That said, the notion that people should never buy one because of the possibility that they may fail outside the (short) one year warranty doesn't make sense. I buy lots of things that I fully understand may break and need repair outside it's warranty period (my car being one of those). It just doesn't make sense (to me) to dismiss every single DA* SDM lens because of possibility it may fail and need its motor replaced at some point down the road.
Stop talking sensibly. You're making the Internets boring.
01-12-2011, 08:50 PM   #104
Veteran Member
sewebster's Avatar

Join Date: Jun 2008
Location: Vancouver, BC
Photos: Gallery
Posts: 533
I wish my car didn't have power windows because they are getting really slow. I'm not sure what this means about SDM lenses though.
01-12-2011, 09:05 PM   #105
Banned




Join Date: Nov 2010
Location: Williston, VT
Posts: 268
QuoteOriginally posted by dgaies Quote
Nobody is actually comparing the two in terms of reliability. I think we can all agree that power windows are orders of magnitude more reliable than the motor in SDM lenses. However, that was hardly the point of the original analogy, and I am fairly certain you knew that.
It's still a terrible, pointless analogy.

However I'll take your ridiculous analogy and make it relevant: imagine a vehicle manufacturer that includes both power windows AND a manual window crank. But you're forbidden to use that crank when the power window motor fails.

Oh, and the power window motor is only warrantied for a year, even though it's failure-prone.

And it's only in the high-end luxury cars that they market to their best customers.
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!
da*, issue, k-mount, lens, pentax lens, people, sdm, sdm lens, slr lens, thread, warranty
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Should I buy this laptop to speed up my workflow or buy a new lens? crossover37 Pentax SLR Lens Discussion 26 09-24-2010 09:41 AM
New 55mm SDM 645D lens means no SDM II? alehel Pentax News and Rumors 11 03-14-2010 09:43 AM
SDM lens, safe to buy? ytterbium Pentax SLR Lens Discussion 126 02-15-2010 04:38 PM
SIGMA 70-200mm f/2.8 II EX DG APO Macro HSM Lens for PENTAX:To buy or not to buy? thelittlecar Pentax SLR Lens Discussion 21 12-31-2009 06:01 AM
Lens offer from Amazon: DA* 50-135 SDM & DA* 16-50 SDM f8 Pentax SLR Lens Discussion 4 03-25-2008 04:45 AM



All times are GMT -7. The time now is 10:02 PM. | See also: NikonForums.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