17-70 Sigma OS absolutely battered clunk clunk :) :(

pimpim · 02-18-2022, 06:50 AM

Hi all,

Bought a Sigma 17-70 OS for less than €100 in "well used" state to see if I can do some smoother video with it.
In general, I think (half) pressing a button to keep the OS active will soon get tiring so I'll abandon that idea

On top of this, something seems broken in the lens I got: the OS literally clunks and shifts the frame as soon as OS kicks in.
It doesn't sound or look healthy. I found a video of someone encountering this in a Sigma OS lens:

You Tube

Anyone experience with this? The video has no mention of a fix.
I can still return it, but depending on if I have to pay postage for the return, might as well keep it.

Considering that something mechanically is really off here, if I just leave off OS and use it as a non-OS lens, would it likely be decentered?

**UncleVanya** · 02-18-2022, 06:55 AM

I assume you have turned off the in body stabilization? If not do. The two systems will otherwise compete.

pimpim · 02-18-2022, 07:13 AM

yeah the clunk happens with the in-body IS turned off.

Fogel70 · 02-18-2022, 08:52 AM

What camera are you using? It may be related to an old bad battery, or if using an older camera with less powerful AA-batteries.
Sigma only used OS for Pentax version of the lenses for a short time, so I think they may have had quality problems with the OS unit on those early lenses.

AfterPentax Mark II · 02-18-2022, 01:36 PM

Originally posted by Fogel70

Sigma only used OS for Pentax version of the lenses for a short time, so I think they may have had quality problems with the OS unit on those early lenses.

It had nothing to do quality problems, but most users thought the OIS was obsolete. So they did not put it in newer or upgraded lenses. The OIS in Sigma lenses is working very well IMNSHO as I learned from a 70-200 f2.8 when I had that for a time and I also own a 50-200 with OIS. Although the OIS unit was removed from the lenses, you paid the same amount for a Pentax (or Sony) mount as for the ones that had OIS installed in the other brands.

pimpim · 02-18-2022, 11:38 PM

Ah this is on K70 but battery was nearly empty. Will try again with a charged battery!

pimpim · 02-19-2022, 01:58 AM

Originally posted by Fogel70

What camera are you using? It may be related to an old bad battery,

same issue with fully charged and relatively new pentax battery - helps confirming the OS is probably defect, seriously thanks for the suggestion!

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02-18-2022, 06:55 AM	#2
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,454	I assume you have turned off the in body stabilization? If not do. The two systems will otherwise compete.

02-18-2022, 07:13 AM	#3
pimpim Senior Member Join Date: Sep 2010 Location: Mainz Photos: Albums Posts: 253 Original Poster	yeah the clunk happens with the in-body IS turned off.

02-18-2022, 08:52 AM	#4
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 3,062	What camera are you using? It may be related to an old bad battery, or if using an older camera with less powerful AA-batteries. Sigma only used OS for Pentax version of the lenses for a short time, so I think they may have had quality problems with the OS unit on those early lenses.

02-18-2022, 01:36 PM	#5
AfterPentax Mark II Pentaxian Join Date: Mar 2021 Posts: 1,467	Originally posted by Fogel70 Sigma only used OS for Pentax version of the lenses for a short time, so I think they may have had quality problems with the OS unit on those early lenses. It had nothing to do quality problems, but most users thought the OIS was obsolete. So they did not put it in newer or upgraded lenses. The OIS in Sigma lenses is working very well IMNSHO as I learned from a 70-200 f2.8 when I had that for a time and I also own a 50-200 with OIS. Although the OIS unit was removed from the lenses, you paid the same amount for a Pentax (or Sony) mount as for the ones that had OIS installed in the other brands.

02-18-2022, 11:38 PM	#6
pimpim Senior Member Join Date: Sep 2010 Location: Mainz Photos: Albums Posts: 253 Original Poster	Ah this is on K70 but battery was nearly empty. Will try again with a charged battery!

02-19-2022, 01:58 AM	#7
pimpim Senior Member Join Date: Sep 2010 Location: Mainz Photos: Albums Posts: 253 Original Poster	Originally posted by Fogel70 What camera are you using? It may be related to an old bad battery, same issue with fully charged and relatively new pentax battery - helps confirming the OS is probably defect, seriously thanks for the suggestion!