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06-26-2012, 10:14 PM   #1
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Failing SDM? Re: 16-50 DA*

Hey there guys. I just switched to my 16-50 DA* lens and I found it not responding to auto focus...

At all.

Flipping the switches, turning the dials, nothing makes the autofocus budge. The 50-135 DA* on the other hand however works just great. I haven't experienced this before, but seems like a busted SDM system to me. What are my options, what should I do now?

06-26-2012, 11:26 PM   #2
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QuoteOriginally posted by Kryscendo Quote
Hey there guys. I just switched to my 16-50 DA* lens and I found it not responding to auto focus...

At all.

Flipping the switches, turning the dials, nothing makes the autofocus budge. The 50-135 DA* on the other hand however works just great. I haven't experienced this before, but seems like a busted SDM system to me. What are my options, what should I do now?
Pray your still in warranty and get it repaired. ?

If not send it in for repair at your cost.

Try to repair yourself there are a few guides that may or may not work, eg DIY SDM repair v1.0

Finally there is the expensive manual lens option if you don't want to pay to get it fixed.
06-27-2012, 01:20 AM   #3
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Try working the focus manually for a while.

You'll also want to try working the lens screw drive a little with a suitable screwdriver.

I've seen people say this has 'resurrected' their dead SDM lenses.
06-27-2012, 07:45 AM   #4
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Yeah screw that shit. The warranty ran up three days ago so I am going to overnight it over to CRIS and hope they fix it. I know they usually do- if not, I'll pay for it.

I never really liked this lens a whole lot either. The zoom adjustment ring always had a little resistance and the damn thing is pretty soft- though it may be my K-r's 12 megapixels doing that.

06-27-2012, 09:43 AM   #5
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this lens on my kx always misfocus, result in soft img..but on my k-5. it works a lot better
at f3.5, the IQ is pretty good. similar to my kit lens at f5.6. at f5.6, definately a prime lens quality.
but too bad I pay 300 bucks to repair the SDM a month ago...
no idea how long it can last...
if the SDM broke one more time, I will just give up this lens. and switch to sigma or tarmon..
06-27-2012, 09:55 AM   #6
Ash
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Sorry to hear that. It's such a fine lens marred by an important physical glitch in its function. Hope the repair works out well for you.
07-09-2012, 12:01 PM - 1 Like   #7
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Turn the camera on and let it sit for at least five or ten minutes before touching a thing. The DA*16-50 has a capacitor in it that gets depleted after the lens has sat unused for a while. That is why high use lenses seldom are reported as having failed. After it has recharged, your lens may come back to life. Mine always does since I learned of this a few years ago and started doing it, and mine is on its second SDM motor after the first really did fail in 2009- (it made squeely noises which are failure signs, which it does not do now, and it has been a few years now on motor number two, so it seems to be true). If you start fiddling with it right after turning it on, the battery will never get a change to recharge the capacitor and the lens won't get itself back to life. You may have to stimulate it manually at first if it took a deep set. Once it starts working, zip it back and forth repeatedly on a low contrast background and it should be good for many days/weeks depending on your capacitor.
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