Sigma 50-150 1:2.8 II APO HSM & K3 II odd behavior

dubi · 06-02-2019, 03:31 AM

I got Sigma 50-150 recently and noticed some odd behavior.

When zoom out to 50 mm, in viewfinder MF starts flashing and screwdrive focusing engages.

The second i zoom in a bit it starts working normally and works great.

Anyone else experienced something like that?

dubi

BarneyL · 06-02-2019, 04:23 AM

Yup, I had the same story + LV autofocus didn't work at all. Sigma service center can fix the weird behavior at the wider end. For LV af, they told me there's no chance to make it work.

dubi · 06-03-2019, 05:55 AM

Thank you for reply.

Did they tell you why it was behaving like that?

BarneyL · 06-04-2019, 05:18 AM

If I recall correctly, it's a matter of how the lens 'introduces' itself to the camera, and a lens firmware tweak could do the trick. For LiveView focusing, they told me the lens uses old type of CPU and it cannot be upgraded anymore to handle contrast detect AF from newer Pentax bodies.

I didn't fix mine, but sold to a K-50 owner instead. It had no PDAF problem there (LV still didn't work, but the buyer didn't care).

**boriscleto** · 06-04-2019, 06:07 AM

Originally posted by BarneyL

Yup, I had the same story + LV autofocus didn't work at all. Sigma service center can fix the weird behavior at the wider end. For LV af, they told me there's no chance to make it work.

How long ago was this? From what I've heard Sigma won't touch a K-mount lens anymore.

BarneyL · 06-04-2019, 07:48 AM

I dug through old emails and it seems that was 2 years ago. As for the price of the service, they said they would take around 30 USD for sole problem diagnosis, but won't charge it if client agrees to the repair. They couldn't say how much would the repair itself cost before they had their hands on the lens. This of course may differ from country to country.

06-02-2019, 03:31 AM	#1
dubi New Member Join Date: Feb 2012 Photos: Gallery Posts: 19	Sigma 50-150 1:2.8 II APO HSM & K3 II odd behavior I got Sigma 50-150 recently and noticed some odd behavior. When zoom out to 50 mm, in viewfinder MF starts flashing and screwdrive focusing engages. The second i zoom in a bit it starts working normally and works great. Anyone else experienced something like that? dubi

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06-02-2019, 04:23 AM	#2
BarneyL Pentaxian Join Date: Feb 2017 Posts: 899	Yup, I had the same story + LV autofocus didn't work at all. Sigma service center can fix the weird behavior at the wider end. For LV af, they told me there's no chance to make it work.

06-03-2019, 05:55 AM	#3
dubi New Member Join Date: Feb 2012 Photos: Gallery Posts: 19 Original Poster	Thank you for reply. Did they tell you why it was behaving like that?

06-04-2019, 05:18 AM	#4
BarneyL Pentaxian Join Date: Feb 2017 Posts: 899	If I recall correctly, it's a matter of how the lens 'introduces' itself to the camera, and a lens firmware tweak could do the trick. For LiveView focusing, they told me the lens uses old type of CPU and it cannot be upgraded anymore to handle contrast detect AF from newer Pentax bodies. I didn't fix mine, but sold to a K-50 owner instead. It had no PDAF problem there (LV still didn't work, but the buyer didn't care).

06-04-2019, 06:07 AM	#5
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,477	Originally posted by BarneyL Yup, I had the same story + LV autofocus didn't work at all. Sigma service center can fix the weird behavior at the wider end. For LV af, they told me there's no chance to make it work. How long ago was this? From what I've heard Sigma won't touch a K-mount lens anymore.

06-04-2019, 07:48 AM	#6
BarneyL Pentaxian Join Date: Feb 2017 Posts: 899	I dug through old emails and it seems that was 2 years ago. As for the price of the service, they said they would take around 30 USD for sole problem diagnosis, but won't charge it if client agrees to the repair. They couldn't say how much would the repair itself cost before they had their hands on the lens. This of course may differ from country to country.