[paulzhere]

Hi all

The million dollar suggestion. "never buy a used DA* 50-135 F2.8 SDM". I broke this suggestion... twice! And I have ended up with two second-hand copies of this lens. One of them has a serial no. in the 911XXXX range and let's call it Mr. OLD and the other has a serial no in the 929XXXX range so let's call it the Ms. NEW. From as far as I could gather, Mr. OLD was manufactured somewhere around early 2010 and Ms. NEW was manufactured around late 2011 or early 2012. Now, of course I just wanna keep one and sell the other one off. But, I am unable to decide between the two! That's where I need your help! My primary criterion for choosing one over the other is lower affinity to SDM failure. I would like to choose the one which has the lower chance of an SDM failure. Of course, I might make the wrong choice or both or neither SDM might fail in the long run. But then I guess I'll just blame my bad luck. Now, the SDM on both of them works perfectly, as I tested them. Neither of them had had an SDM failure in the past as attested by the sellers and they are trustworthy sellers. Ms. NEW has visited the service center once and they cleared her claiming she was in perfect condition with no defects whatsoever. I list the pros and cons of both of them below:

Mr. OLD cons:
1. Well, old!
2. More beat-up than Ms. NEW. So it has evidently taken more usage.

Mr. OLD pros:
1. Just the fact that it has taken more use, makes it more rugged (?) Feels more rugged anyway (maybe it's just me).
2. Focuses perfectly on my K-3. Didn't require any autofocus fine adjustments.
3. The internal parts seem less noisy while focusing continuously. Don't get me wrong, of course the lens is SDM and so is totally silent. but there's always a small "whirring" sound when the focus ring turns. Maybe that's the internal parts rotating. Anyway, there's lesser noise in Mr. OLD than Ms. NEW.
4. Cost a good EUR 100 less than Ms. NEW.

Ms. NEW cons:
1. Needed a +5 fine adjustment on my K-3.
2. Then internal parts seem noisier than Mr. OLD while continuous autofocus.
3. Cost EUR 100 more than Mr. OLD.

Ms. NEW pros:
1. It's mint! Almost pristine!
2. The fact that it has been to the service center once and has been cleared as having no problems might testify for it's longevity (?)

Any suggestions, guys?

[pathdoc]

Sod's law says life is six to five against. Are you sure Ms New isn't operating in screwdrive mode, having previously been deactivated? (If so, you are safe. If not, the internal noises may point to problems.)

If the SDM fails, it can always be deactivated and you can default to screwdrive.

[Adam]

Which one have you used more? SDM is more prone to failure if you just leave it on the shelf for extended periods of time.

[paulzhere]

Sod's law says life is six to five against. Are you sure Ms New isn't operating in screwdrive mode, having previously been deactivated? (If so, you are safe. If not, the internal noises may point to problems.)

If the SDM fails, it can always be deactivated and you can default to screwdrive.

Thanks for the reply pathdoc. Yes, I'm dead sure it's operating on SDM. It's only very very slightly noisier than the other one. I'm sure it's the infernal parts. I'm aware of the conversion to screwdrive on the K5. Can it be done on the K3 as well?

---------- Post added 06-26-16 at 02:25 PM ----------

Which one have you used more? SDM is more prone to failure if you just leave it on the shelf for extended periods of time.

True. The problem is I only procured them a couple of days back so didn't get a chance yet to use either one extensively...

[Mistlefoot]

What you paid for each is less material then what you will sell each for. If you are of the type to sell for less because you bought for less than it might be advantageous for you to sell the one that will bring you the most money. If you are 50/50 on which one to keep that might be the decider. That it is "more beat up" might get you less money for it as well.

[paulzhere]

What you paid for each is less material then what you will sell each for. If you are of the type to sell for less because you bought for less than it might be advantageous for you to sell the one that will bring you the most money. If you are 50/50 on which one to keep that might be the decider. That it is "more beat up" might get you less money for it as well.

Thanks, that's a good suggestion. But I was thinking I'll just put it on the bay and let auction take its course...

[Prakticant]

Any suggestions, guys?

Why not to make some real-life tests (picture quality - i.e. sharpness at f=2.8 at both 50mm and 135mm ends at infinity and close-up distance?)