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Hi,

I've experienced strange behaviour on my DA* 50-135. When connected to the Pentax K-7, it doesn't respond to AF.

It takes up to 2 minutes to have it fully operational with the SDM. I've cross-checked with my other lenses: both the DA* 16-50 and DA* 60-250 work instantly.

So I sent my DA* 50-135 to be repaired. Verdict is the SDM motor needs to be changed Total cost : 300 EUR / USD

This is very disappointing for a prime lens . According to many forums, it seems to be a common issue.

So the question is Has one of your Pentax DA* SDM lens failed

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--- rei_vilo
Pentax K-5 + BG4 + DA* 16-50 + DA* 50-135 + DA* 60-250 + AF-540FGZ
reivilophotography.weebly.com

Isn't it a zoom and not a prime lens?

Haven't had a problem with mine, but it is rather new. I've had Sigma HSM lenses for a while and their motors have yet to fail. I take it that your lens is out of warranty?

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PhilipGoh.com

Haha, only two votes so far. There really are that few Pentax users on this forum

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PhilipGoh.com

There are more but not all of them have SDM lenses

Hi Rei,

Ouch! That's very disappointing news though I guess I can see why it might be costly to repair after factoring in labour, parts and shipping. But, for a prime lens ("prime" in the sense of being one of the best) announced only three years ago, it's a shame that Pentax don't offer that the failure was down to a manufacturing defect and make a suitable adjustment to the cost of repair.

Bob.

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OM-D E-M5 + ED 12-50mm, H-PS14042E, H-F007014E, L-RS014150E, M.ZUIKO DIGITAL 45mm 1:1.8.
Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.

Bonsoir Bob,

Thank you for your post. Actually, Pentax no longer deals directly with customers for after-sales service. Customers should pass through retailers.

The SDM motor failure is mentioned in various forums, with some pentaxians being very vocal. Compiling the feed-back, SDM lenses seem to be very sensitive to 'impact damage'. Since I take great care of my gear, I'm surprised (understatement) .

I purchased one of the first lens available in France. Maybe quality wasn't on top.

Before being inert, my DA* 50-135 did a stuck focusing. In that case, the SDM motor was moving the AF painfully and slowly, as if the motor weren't powerful enough

My other SDM lenses, the 2 years old 16-50 and the 6 months old 60-250, both work perfectly and the ultrasonic motor is a true delight, fast and quiet. The 50-135 is the only one featuring internal zoom.

Anyway, I'm waiting for my lens and I hope I'll receive it soon before Spring

_________________
--- rei_vilo
Pentax K-5 + BG4 + DA* 16-50 + DA* 50-135 + DA* 60-250 + AF-540FGZ
reivilophotography.weebly.com

Bonsoir pgtips,


Pentax offers three ranges of lenses: DA, DA limited and DA*. Check how I went from DA to DA*

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--- rei_vilo
Pentax K-5 + BG4 + DA* 16-50 + DA* 50-135 + DA* 60-250 + AF-540FGZ
reivilophotography.weebly.com

This apparently has become quite an issue. I have been hearing more and more about this over the web for months. It makes me want to re-think about buying the 50-135mm as I have been saving for one.

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I would put very little stock in what you read on the internet. If go by what the Pentax forums say then:
1) SDM lenses are total failures.
2) Pentax cameras cannot autofocus.
3) The K-7 doesn't work in low light.
4) Pentax is doomed.

None of these is true of course

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PhilipGoh.com

Your probably right Phil

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