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Photo 5 Jul 4, 2013 11:57 AM

Simga 17-70mm for Pentax Issue Resolved
Recently I purchased a new Sigma 17-70mm for use on my K-5/K-5ii. When I received it I was not able to get usable images unless the camera was set at ISO3200 and shutter was in area of 1/30-1/40th second. Cleaning image sensor with bulb blower didn't help much. After some time I found a strange fix for the problem -- turn the in camera body Image Stabilizer off. Once I did that the lens worked perfectly.

Posting in case this can help someone else.


Photo 5 Jul 6, 2013 10:15 AM

TCav followed up with this message to me and I want to st it here. May be an issue with the lens I will contact Sigma and report back

From TCav-- I just checked with the Sigma website. It says there that the 17-70 doesn't have OS for the Sony and Pentax mount. Something doesn't sound right. Did you check with Sigma?

Photo 5 Jul 6, 2013 10:51 AM

I called Sigma I had to hang up on them the first time and call back got some guy who couldn't speak English. Then got a women second time. She was very smart, said sounds like focusing motor is messed up in the lens she is gonna e-mail me a pre-paid label to send it direct to them to look at and if its bad they will send me a new one. And she confirmed they leave the Image Stabilization Mode out so their are not optical focus issues with this lens

mtngal Jul 6, 2013 12:59 PM

It does sound like there's something wrong with the electronics of the lens, think that sending it back for replacement makes the most sense.

Photo 5 Jul 7, 2013 11:08 AM

Sigma came through with an e-mail in less than 3 hours with a pre-paid shipping label for me to send the lens back to the them; they told e not to send it back to the person/shop that sold it to me. Will be mailed out tomorrow.

jelow1966 Jul 7, 2013 12:19 PM

Good to hear. My understanding is that while Sigma has issues with QC out of the factory they are very good at fixing them for the user. Just a bit of a pain.


snostorm Jul 9, 2013 6:01 PM

It's been suggested that Sigma hasn't purchased licensing rights from the OEMs to make their lenses completely compatible with the now universally chipped lenses from the camera makers. The fact that exif usually misreports the lens model used seems to confirm this. It could be that the chip they used in the lens was totally inappropriate for the FL range of the lens and this made the SR system go wonky.

Both of the Sigma lenses that I use with my 1.7x AFA report incorrect aperture values throughout the range, so other anomalous behavior is no real surprise to me.

As long as they take care of the problem, I'd be satisfied.


Photo 5 Jul 18, 2013 9:52 AM

Quick update sigma e-mailed me saying they looked at the lens and it does have motor focusing issues. They said they will be dealing with the issue today and will report back

Photo 5 Jul 18, 2013 7:15 PM

Well they are replacing the motor focus drive in the lens ans will send the lense back to me. Will be shipped no later than Monday morning.

mtngal Jul 19, 2013 2:17 PM

That's quick service! Glad to hear that Sigma is supporting the lens and responding quickly to your problem.

Photo 5 Jul 25, 2013 11:12 AM

Lens is back just need some good weather to get out and test it out

Photo 5 Jul 26, 2013 1:45 PM

Its working very well looks like they fixed but have will be doing an extensive test with it on Sunday or Monday to make sure

mtngal Jul 27, 2013 11:37 PM

Post pictures and let us know how you find it after your test.

Photo 5 Jul 31, 2013 7:32 AM

It is working perfectly. AF is super fast and when using LR4 to view my images I can magnify them up to 100% and they are still spot on sharp and clear. I will try to post a few images later today.

Photo 5 Aug 3, 2013 12:19 PM

Having issues posting images here ever time I get the images 90%$ load it just stops loading and the forum locks up. Will try again later

Photo 5 Aug 10, 2013 5:10 PM

Still having issues posting images. When I do downsize (to try to speed up he upload etc) I notice the images look crappy compared to my original images..... so I have given up with trying to post a few images here. It seems each time I have come on here over the past year or so and tried to upload images it gets harder and harder........ it must be something on my end because people are posting photos here all the time

mtngal Aug 10, 2013 11:53 PM

I have my pictures hosted on a separate photo hosting site, then post a link here that shows the picture embedded in the post. That way I don't have to worry as much about file size, just dimensions so I don't go too wide. I use zenfolio which will take a larger picture and resize it gracefully, not like the software here which is very hard when it downsizes. When I was uploading the files here, I always made sure that the longest size was 800 pixels and the file size small by resizing and compressing the file with PSE.

Photo 5 Aug 11, 2013 6:50 PM

Thanks when I have more time I will investigate that

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