Sigma DC 17-70 2.8-4 Macro HSM OS - AF issues

Steve.Ledger · 10-11-2014, 11:14 PM

I just received a used Sigma DC 17-70 2.8-4 Macro HSM OS
It's in great cosmetic condition and all works great with the exception that in Live view AF almost always fails at the 70mm end even though I get the focus confirmation beep and the focus point illuminates green the LV image is way out of focus.
I get a hit rate of about 1 in 5 AF attempts.
Shorter focal lengths are all fine.

Note that this is in Live View only - so CADAF is used. PDAF via the OVF is fine at all focal lengths.
Yes I have tried different metering, focus active area and aperture settings.

The behavior is the same when mounted on the K-50 and the K-01, so that eliminates it being a camera problem.

Has this issue come up before with other HSM lenses, or do I have a dud?

---------- Post added 10-12-14 at 04:20 PM ----------

BTW: The reason I bought the lens was for the OS and it is wonderful! It totally solves the horrid Movie SR problem with the K-50 and K-01 when shooting hand held video.

Attached Images

**i_trax** · 10-12-2014, 12:21 AM

Rather odd , I have 2x of ver 1 ( 17-70 2.8-4.5 MACRO non OS/HSM) and 1x ver 3 ( 17-70 2.8-4 non OS Macro HSM Contemporary ) and I never noticed any focus problems in LV but I do not make movies.
I just tested Sigma ver1 with K-3 and K-30 ( more less identical to K-50 ) and focus locks in LV at 70mm very fast and precise. I will test the other Sigmas tomorrow ( do not have them with me).
kind regards
jack

Steve.Ledger · 10-12-2014, 12:35 AM

Originally posted by i_trax

Rather odd , I have 2x of ver 1 ( 17-70 2.8-4.5 MACRO non OS/HSM) and 1x ver 3 ( 17-70 2.8-4 non OS Macro HSM Contemporary ) and I never noticed any focus problems in LV but I do not make movies.
I just tested Sigma ver1 with K-3 and K-30 ( more less identical to K-50 and focus locks in LV at 70mm very fast and precise.

Thanks for the reply.
If both of your V1s are non OS/HSM that mean a significant difference in the optics construction and AF system I would imagine.
It's not just when shooting video, it happens even when shooting stills using LV. Just so happens that I'm mostly going to shoot a video clip if I'm in LV.

**i_trax** · 10-12-2014, 01:41 AM

Hi, actually I do have Sigma ver 3 ( 17-70 2.8-4 non OS Macro HSM Contemporary ) with me, and again on K3 and K30 there is no problem with AF in LV.
Very odd, hopefully someone will replay who owns ver2 ( with OS like yours), unfortunately this lens with OS was sold very briefly in Pentax mount, so not many of them around.

JinDesu · 10-12-2014, 03:49 AM

This happens with some Sigma HSM lenses, and some Tamron lenses in screwdrive. In both cases, the manufacturer can fix it. In Sigma's case (I used to have the 17-70 HSM non-C), I sent it to Sigma saying that the lens wouldn't AF in live-view on my k-x or my k-01 - and another member had suggested that I mention the GMR sensor. After doing that, they sent it back updated and it proceeded to work very well in liveview mode.

Steve.Ledger · 10-12-2014, 12:14 PM

It would have to go back to Japan and would cost too much making the 'used lens' saving a bad deal.
I'm disappointed the seller wasn't upfront about any issues. I will just have to MF at the long end.

**i_trax** · 10-12-2014, 08:56 PM

ver1 and ver3 on K-5, occasional problem at 70mm at low light.
ver1 and ver3 on K-01 no problems and much faster focus locking than K-5.
No you do not need to send it back to Japan, take it to CR Kennedy , they are Sigma/Pentax AU distributors, they are very helpful.
Years ago my first ver1 Sigma ( way out of warranty) lost some aperture blades , I took it to Perth office and asked for a quote.
Two weeks later I was asked to pick it up, they gave me a brand new lens ( possibly reconditioned ) at no charge , it came with a hood so have a spare one, I was speechless.
Well the person in Japan possibly did not use LV ( I hardly ever use it) , yes most likely the GMR sensor needs to be adjusted / replaced
good luck

JinDesu · 10-12-2014, 09:01 PM

Originally posted by Steve.Ledger

It would have to go back to Japan and would cost too much making the 'used lens' saving a bad deal.
I'm disappointed the seller wasn't upfront about any issues. I will just have to MF at the long end.

Are you in the U.S.? You could try asking Sigma US about it. They are pretty reasonable about these things (in my experience).

Steve.Ledger · 10-12-2014, 09:26 PM

No, Australia..

Casion · 12-01-2014, 11:02 AM

Originally posted by Steve.Ledger

Has this issue come up before with other HSM lenses, or do I have a dud?

I believe that this is not the problem of HSM lenses. My K-5 II sometimes misses focus in Live View heavily.

10-11-2014, 11:14 PM	#1
Steve.Ledger Veteran Member Join Date: Oct 2009 Location: Far North Qld Posts: 3,301	Sigma DC 17-70 2.8-4 Macro HSM OS - AF issues I just received a used Sigma DC 17-70 2.8-4 Macro HSM OS It's in great cosmetic condition and all works great with the exception that in Live view AF almost always fails at the 70mm end even though I get the focus confirmation beep and the focus point illuminates green the LV image is way out of focus. I get a hit rate of about 1 in 5 AF attempts. Shorter focal lengths are all fine. Note that this is in Live View only - so CADAF is used. PDAF via the OVF is fine at all focal lengths. Yes I have tried different metering, focus active area and aperture settings. The behavior is the same when mounted on the K-50 and the K-01, so that eliminates it being a camera problem. Has this issue come up before with other HSM lenses, or do I have a dud? ---------- Post added 10-12-14 at 04:20 PM ---------- BTW: The reason I bought the lens was for the OS and it is wonderful! It totally solves the horrid Movie SR problem with the K-50 and K-01 when shooting hand held video. Attached Images

10-12-2014, 12:21 AM	#2
i_trax Loyal Site Supporter Join Date: Jan 2011 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 2,621	Rather odd , I have 2x of ver 1 ( 17-70 2.8-4.5 MACRO non OS/HSM) and 1x ver 3 ( 17-70 2.8-4 non OS Macro HSM Contemporary ) and I never noticed any focus problems in LV but I do not make movies. I just tested Sigma ver1 with K-3 and K-30 ( more less identical to K-50 ) and focus locks in LV at 70mm very fast and precise. I will test the other Sigmas tomorrow ( do not have them with me). kind regards jack Last edited by i_trax; 10-12-2014 at 01:34 AM.

10-12-2014, 12:35 AM	#3
Steve.Ledger Veteran Member Join Date: Oct 2009 Location: Far North Qld Posts: 3,301 Original Poster	Originally posted by i_trax Rather odd , I have 2x of ver 1 ( 17-70 2.8-4.5 MACRO non OS/HSM) and 1x ver 3 ( 17-70 2.8-4 non OS Macro HSM Contemporary ) and I never noticed any focus problems in LV but I do not make movies. I just tested Sigma ver1 with K-3 and K-30 ( more less identical to K-50 and focus locks in LV at 70mm very fast and precise. Thanks for the reply. If both of your V1s are non OS/HSM that mean a significant difference in the optics construction and AF system I would imagine. It's not just when shooting video, it happens even when shooting stills using LV. Just so happens that I'm mostly going to shoot a video clip if I'm in LV. Last edited by Steve.Ledger; 10-12-2014 at 12:44 AM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
For Sale - Sold: Sigma 17-70 Macro HSM 2.8-4.0 (Non OS version)	zbrueningsen	Sold Items	2	01-07-2014 01:59 PM
For Sale - Sold: Sigma AF 17-70mm f/2.8-4 DC HSM OS macro for Pentax w/Hoya UV filter	gstool	Sold Items	6	03-01-2013 06:52 PM
Sigma 17-70 F2.8-4 DC Macro OS HSM	Elliot	Ask B&H Photo!	3	12-27-2012 11:27 AM
Sigma 17-70mm f/2.8-4 DC Macro OS HSM Lens	infos	Pentax SLR Lens Discussion	11	10-18-2012 09:03 PM

10-12-2014, 01:41 AM	#4
i_trax Loyal Site Supporter Join Date: Jan 2011 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 2,621	Hi, actually I do have Sigma ver 3 ( 17-70 2.8-4 non OS Macro HSM Contemporary ) with me, and again on K3 and K30 there is no problem with AF in LV. Very odd, hopefully someone will replay who owns ver2 ( with OS like yours), unfortunately this lens with OS was sold very briefly in Pentax mount, so not many of them around.

10-12-2014, 03:49 AM	#5
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	This happens with some Sigma HSM lenses, and some Tamron lenses in screwdrive. In both cases, the manufacturer can fix it. In Sigma's case (I used to have the 17-70 HSM non-C), I sent it to Sigma saying that the lens wouldn't AF in live-view on my k-x or my k-01 - and another member had suggested that I mention the GMR sensor. After doing that, they sent it back updated and it proceeded to work very well in liveview mode.

10-12-2014, 12:14 PM	#6
Steve.Ledger Veteran Member Join Date: Oct 2009 Location: Far North Qld Posts: 3,301 Original Poster	It would have to go back to Japan and would cost too much making the 'used lens' saving a bad deal. I'm disappointed the seller wasn't upfront about any issues. I will just have to MF at the long end.

10-12-2014, 08:56 PM	#7
i_trax Loyal Site Supporter Join Date: Jan 2011 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 2,621	ver1 and ver3 on K-5, occasional problem at 70mm at low light. ver1 and ver3 on K-01 no problems and much faster focus locking than K-5. No you do not need to send it back to Japan, take it to CR Kennedy , they are Sigma/Pentax AU distributors, they are very helpful. Years ago my first ver1 Sigma ( way out of warranty) lost some aperture blades , I took it to Perth office and asked for a quote. Two weeks later I was asked to pick it up, they gave me a brand new lens ( possibly reconditioned ) at no charge , it came with a hood so have a spare one, I was speechless. Well the person in Japan possibly did not use LV ( I hardly ever use it) , yes most likely the GMR sensor needs to be adjusted / replaced good luck

10-12-2014, 09:01 PM	#8
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	Originally posted by Steve.Ledger It would have to go back to Japan and would cost too much making the 'used lens' saving a bad deal. I'm disappointed the seller wasn't upfront about any issues. I will just have to MF at the long end. Are you in the U.S.? You could try asking Sigma US about it. They are pretty reasonable about these things (in my experience).

10-12-2014, 09:26 PM	#9
Steve.Ledger Veteran Member Join Date: Oct 2009 Location: Far North Qld Posts: 3,301 Original Poster	No, Australia..

12-01-2014, 11:02 AM	#10
Casion Senior Member Join Date: May 2013 Posts: 103	Originally posted by Steve.Ledger Has this issue come up before with other HSM lenses, or do I have a dud? I believe that this is not the problem of HSM lenses. My K-5 II sometimes misses focus in Live View heavily.