[sTi]

BTW, post the message you send to Sigma. Maybe we can send the same message to local Sigma centers in our respective countries. Thanks!

Here are my results, and they were typical with multiple tries. I focused on the cup using AF.S:

Thanks for your images that demonstrate the problem.

I've now written to Sigma and await their reply. Here's the English translation of what I wrote:

Sigma 17-70 "Contemporary" for Pentax: compatibility problems with "Shake Reduction" function

Apparently the 17-70 "Contempary" lens suffers from some compatibility issues with the "Shake Reduction" (SR) function of Pentax cameras. I have written a report in the largest English-language forum for Pentax cameras (+Link to this thread)

As can be seen from the metadata of image files, the problem arises due to incorrect values for the parameter "SR focal length" at wide angle. This leads to a malfunction of the SR function in the cameras as it assumes a wrong focal length (e.g. 66mm instead of 17mm), which may result in blurred images. As can be seen in the forum thread, the problem has been confirmed by other users of the lens with various current and older camera models (K-3, K-5II, K-5IIs, K-5).

I would appreciate it if you could investigate this problem or pass it on to the appropriate place. I'd be happy to update the review accordingly as soon as I get more information from you. Of course the question whether this problem can be expected to be fixed by a firmware update will be of particular interest to users of the lens.

Best Regards
...

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Last edited by sTi; 01-08-2015 at 02:31 AM.

[Nitrogliserin]

I did a quick test and results are as OP has mentioned.



SR OFF


SR ON


Desired results should have been reverse. Don't you think so?

Both photos are on ISO 1600 but with SR ON it looks much more noisy.

[Spodeworld]

Thanks

I used your text as the basis for my submission to Sigma, which was just sent a few miniutes ago. I suggest that everyone concerned about it contact Sigma with the same message.

Here is the link in the US:
Contact Us | Sigma Corporation of America



Message sent to Sigma:

Sigma 17-70 "Contemporary" for Pentax: compatibility problems with "Shake Reduction" function

Apparently the 17-70 "Contempary" lens suffers from some compatibility issues with the "Shake Reduction" (SR) function of Pentax cameras. A new report has been just written in the largest English-language forum for Pentax cameras (https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/285104-sigm...reduction.html)

As can be seen from the metadata of image files, the problem arises due to incorrect values for the parameter "SR focal length" at wide angle. This leads to a malfunction of the SR function in the cameras as it assumes a wrong focal length (e.g. 66mm instead of 17mm), which may result in blurred images. As a matter of fact, I was able to achieve sharp images at 17mm at 1/15" handheld with SR off, but not able to do so once the SR was turned on due to the overcompensation resulting from the incorrect 'SR focal length' values being passed. As you can imagine, this is extremely distressing to anyone who owns this lens or is considering this lens as this is a fine piece of glass that appears to have been compromised by systemic error.

As can be seen in the forum thread, the problem has been confirmed by other users of the lens with various current and older camera models (K-3, K-5II, K-5IIs, K-5).

I would appreciate it if you could investigate this problem or pass it on to the appropriate place. I'd be happy to update the review accordingly as soon as I get more information from you. Of course the question whether this problem can be expected to be fixed by a firmware update will be of particular interest to users of the lens as well as potential future customers of Sigma products.

Best Regards

Steven Brener

Thanks for your images that demonstrate the problem.

I've now written to Sigma and await their reply. Here's the English translation of what I wrote:

[sTi]

I did a quick test and results are as OP has mentioned.

SR OFF
SR ON

Desired results should have been reverse. Don't you think so?

Thanks for your test with the K-30.
Of course you are right, if SR would function normally with this lens the "SR on" picture should generally show less camera shake than with "SR off". Let's hope Sigma can fix this issue.

[reeftool]

It will be interesting to see their reply, if you get one. Will they address the issue or blame the problem on the Pentax SR system? Since I tend to avoid those shutter speeds when shooting handheld, it's something I never noticed in my photos so I'm not really concerned. Since most of my non landscape wide shots will probably involve people, I will have a faster shutter speed simply because people naturally tend to twitch and move, even in "posed" shots.

Where will the buck stop? I can understand the SR hunting during a half press but the data also records whether the photo was stabilized or not and the wrong data shows in stabilized shots. Since the camera is properly recording the focal length, why is the SR stabilizing a 17mm lens as a 45 or 52 mm? This may not be a Sigma issue.

[sTi]

Where will the buck stop? I can understand the SR hunting during a half press but the data also records whether the photo was stabilized or not and the wrong data shows in stabilized shots. Since the camera is properly recording the focal length, why is the SR stabilizing a 17mm lens as a 45 or 52 mm? This may not be a Sigma issue.

It's difficult to say where the problem originates without having inside knowledge of the K-mount communication protocols - maybe the Sigma lens sends incomplete or wrong data to the camera, maybe the camera misinterprets something because it does not fully recognize the lens ID, or maybe something completely different is the problem. However, I'm pretty certain Pentax will feel no responsibility to do anything about it because SR works perfectly with original Pentax lenses. Our only chance is Sigma doing something about it (if it's even technically possible) I'm afraid...

[Spodeworld]

Here is the reply I got from Sigma:

"Hello Steven,
We are presently not experiencing this situation but I will forward this to our engineers in Japan for investigation.
Yours Truly,
Paul Pizzano
The Sigma Corp. of America"

Looks like we need more and more people to contact Sigma about this! Please contact Sigma.

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Last edited by Spodeworld; 01-08-2015 at 12:06 PM.

[Nitrogliserin]

I've sent an e-mail to Sigma UK. (same email text above)

IMO this investigation in Japan can take forever.

And in the end I don't want to end up buying Sigma dock. There must be an alternative solution.

[Spodeworld]

Great. We need as many people as possible to contact Sigma.

As far as a dock is concerned, it may have use for future lens/camera purchases, but first and foremost I'd like a solution, even if that's what it takes.

I'm wondering if Adam can promote this as it would be good for as many Pentax users to see this as possible.

I've sent an e-mail to Sigma UK. (same email text above)

IMO this investigation in Japan can take forever.

And in the end I don't want to end up buying Sigma dock. There must be an alternative solution.

[Nitrogliserin]

I'm wondering if Adam can promote this as it would be good for as many Pentax users to see this as possible.

That would be great and much more result oriented. Perhaps this is a minor issue for Pentax engineers and they can make a hotfix. Who knows?

[MadMathMind]

It's difficult to say where the problem originates without having inside knowledge of the K-mount communication protocols - maybe the Sigma lens sends incomplete or wrong data to the camera, maybe the camera misinterprets something because it does not fully recognize the lens ID, or maybe something completely different is the problem. However, I'm pretty certain Pentax will feel no responsibility to do anything about it because SR works perfectly with original Pentax lenses. Our only chance is Sigma doing something about it (if it's even technically possible) I'm afraid...

I have two other Sigma lenses that do not display this issue. My 70-200mm HSM II (a bit older, I think around 2009 or 2010) is always within a couple mm of the reported focal length. That makes sense that the two not be 100% identical because if they always are, then why both having two separate parameters?

I checked about 10 of my images with the Sigma 18-35 f/1.8. Those were 100% identical. Now, this is a lens that has been reported to have major focus issues (which I have not seen to nearly the extent of what others have), which are most assuredly something miscommunicating between the lens and body.

If the issue is in the lens, it seems to be unique to the 17-70. I never noticed the issue because I avoided those low shutter speeds. Come to think of it, I think I did so because the pictures didn't come out so well. I had always assumed that 1/10 is just too slow, even with shake reduction. But I am able to hold the 18-35 at the wide end at that shutter speed and have even gone down as low as 1/6 with limited success. (Anything slower....forget it.)

[Spodeworld]

Then please contact Sigma with this info. Based on their response to me it seems like they are unaware of this. They will be more inclined to fix the problem if more people bring it to their attention. Thanks

I have two other Sigma lenses that do not display this issue. My 70-200mm HSM II (a pbit older, I think around 2009 or 2010) is always within a couple mm of the reported focal length. That makes sense that the two not be 100% identical because if they always are, then why both having two separate parameters?

I checked about 10 of my images with the Sigma 18-35 f/1.8. Those were 100% identical. Now, this is a lens that has been reported to have major focus issues (which I have not seen to nearly the extent of what others have), which are most assuredly something miscommunicating between the lens and body.

If the issue is in the lens, it seems to be unique to the 17-70. I never noticed the issue because I avoided those low shutter speeds. Come to think of it, I think I did so because the pictures didn't come out so well. I had always assumed that 1/10 is just too slow, even with shake reduction. But I am able to hold the 18-35 at the wide end at that shutter speed and have even gone down as low as 1/6 with limited success. (Anything slower....forget it.)

[rextang]

Can anyone test whether it has something to do with what angle (relative to horizontal) you hold the camera at the time the photo is taken? I'm not familiar with the gyro mechanism, but the gyro may have the most latitude to fix shake when shooting horizontal and the mechanism offers float equally in all directions on the focal plane. The theory I'm throwing out there is that at an angle the mechanism maxes out at its physical limit and you are not getting any SR at all, or blur is introduced when the mechanism starts bouncing off its physical limiters when shooting downward, upward, etc.
Perhaps it's some combination of incorrect data and the function of SR together that is causing the problem. Test away.

[MadMathMind]

Then please contact Sigma with this info. Based on their response to me it seems like they are unaware of this. They will be more inclined to fix the problem if more people bring it to their attention. Thanks

I no longer own the lens. If they want information or ask me to do something, I can't. I'd worry they'd see this as wasting time and not take listen to serious requests.

[Spodeworld]

Has anybody else received any responses from Sigma? Based on mine, it seems like I am the only one they have ever heard this from. That's not encouraging if we're hoping for a fix.