[Craig66]

I think I've come across a problem with my K3-ll. But only with my just repaired and returned today Sigma 70-200mmF2.8 ll Macro lens is attached.
The other week, my Sigma 70-200F2.8-ll auto focus died. Just before it stoped working, while on my K3-ll I noticed that when it was at 70mm zoom, the auto focus wouldn't work. I would get a MF flashing in the view finder. If I zoomed it in just a little, between 75 and 80mm it would work. I tried it on my K20D, worked fine from 70 through to 200mm. Put it back on the K3-ll worked from 75/80mm through to 200mm fine, but not at 70mm. Then it died, stoped working all together, even on the K20D.


Sent it to Melbourne, C.R.Kennedy, Australian Pentax/Sigma. Got it back today. New 065 Rotor, new Stator ring+ Labour. $256.15. Stuck it on my K3-ll to give it a run. Guess what, Lens works, but not at 70mm zoom. Same thing as before. Works great from 75/80mm through to 200mm, but not at 70mm. Put it on the K20D, works fine from 70mm through to 200mm Back on the K3-ll, dup. Nothing at 70mm, fine from 75/80mm.
Put it on the K20D again. Yep works fine. Put it on my K10D. Yep, works fine.


Has to be something wrong with my K3-ll, right ?? That's what I'm now thinking. It's probably what killed the auto focus on the 70-200 in the first place. My Sigma 50-500 works fine on it, my DA*200, with and without TC works fine. But the 70-200 wont at 70mm. But will from 75/80mm up. I just don't get it.


My K3-ll is in the affected serial range for the not powering off/GPS problems. But I've had no problems, other than this with the Sigma 70-200F2.8-ll


Looks like the K3-ll is going on a holiday back to C.R.Kennedy next week..


Anyone else with a K3-ll having similar troubles with auto focus on Sigma lenses...

[jawsy]

I've got the same combo and came from a K20D too but no issues.

Has anyone picked up your K-3ii other than yourself with the 70-200 attached? Just wondering if picking up by the DLSR body has damaged the mount ring contacts? A bit out there I know, but I've had to pull up my partner once or twice before they did that. Does the K-3ii work on smaller lenses?

[tduell]

Anyone else with a K3-ll having similar troubles with auto focus on Sigma lenses...

No problems here with my Sigma 18-300 F3.5-6.3 DC Macro HSM lens.
My K-3 II is also within the list of suspects, but thus far has been performing flawlessly.
I don't like hearing stories like yours, it makes me feel like I might be next!
Commiserations, and I hope all is sorted out quickly and cheaply.

Cheers,
Terry

[donpjt]

Did you try shooting on AF-C mode instead of AF-S.

[Craig66]

Nobody has touched, picked it up. My other lenses seem to work fine, it's just the 70-200, and only when it's at 70 to about 75mm zoom setting. from 75mm'ish and up it works fine, so far. I tried AF-S and AF-C, all the same. mount ring contacts look good. But I'm no expert. Just seems very strange that it's only at 70 to about 75mm zoom that it wont work. But works fine if I'm at 75'ish and above.

I've stopped using it, because that's what it was doing the other week, just before the auto focus stop working altogether. I'm scared the lens will die again, and don't want to risk any of my lenses on it.


I use the 70-200 to shoot dirt bikes mainly. But haven't done any since getting my K3-ll 3 months ago. Didn't think to try it then. So I only tried it on the K3-ll the day before the lens died. About 3 weeks ago. Soon as I put it on I noticed it wouldn't auto focus at wide zoom, 70 to about 75mm, but was fine above. Next day shooting birds in the back yard it just stoped working. Sent it in got it fixed. back yesterday. Doing the same thing. I thought it was the lens that had the problem. But now I think it's the K3-ll


I've contacted Pentax Australia. Waiting to hear from them. I'll send the K3-ll back next week, see if they will replace it for another one.. One that's above the affected serial range too. Hopefully they will.. I really don't want to risk putting a lens on it. Screw drive maybe, but not SDM or lens motor.


Not looking good for me wanting to jump into a FF or any new Pentax lenses. Not with the issues the K3-ll's are having.

[eraser]

I noticed something similar with my Sigma HSM II 70-200 2.8.
On my K3-II it will switch back and forth between AF and MF rapidly. Sometimes works fine, sometimes doesn't. Works fine on my K5IIs.
My K3-II is also in the power recall range and is going in for repair this weekend.

[jawsy]

Sent it in got it fixed. back yesterday.

What did CR say the fault was? If it was mechanical it won't be related to the K-3ii. If was electrical, the possibility is still there.

[tduell]

My K3-II is also in the power recall range and is going in for repair this weekend.

Did CR Kennedy contact you about this, or have you decided to force the issue based on published serial numbers?
I checked mine against the serial numbers published in PF, and then contacted CRK via email, asking for advice, but never got any response.

Cheers,
Terry

[eraser]

Did CR Kennedy contact you about this, or have you decided to force the issue based on published serial numbers?
I checked mine against the serial numbers published in PF, and then contacted CRK via email, asking for advice, but never got any response.

Cheers,
Terry

I went based on my serial number being in the affected range and having some weird issues where both main and grip batteries were drained to zero. Also seems like I am getting lower battery life than I would expect.
Called Pentax and was referred to Sun Camera (I'm in Canada) for service and they said send it in. Nobody asked for my serial number at any point, heh.

Was there a firmware update for the 70-200 for some issue related to this or am I remembering wrong?

[jawsy]

Well, I've just done my bit for the greater good. I'm one of these types that will fiddle with something that's slightly broken until it's well and truly stuffed.

I've got something coming up where I'll need the K-3ii / HSMII combo at 70mm so I spent an hour this morning giving it a workout at 70mm. Not exactly scientific, but I can report that I couldn't induce the same issues you have. I did notice that at 70mm, the inner lens elements are thrust fully forward in the barrel. It got me thinking as to whether you may simply have a wear or contamination issue related to the mechanism operating at the edge of it's mechanical stroke (i.e. a high friction fault.) It doesn't explain as to why the issue disappears on the K20D though. The issue may still be there, but if the K20D delivers slightly more voltage/current to the lens under load, it may be capable of driving through it and masking the problem. As I was saying in a previous post, it would be worth clarifying with CRK as to whether the rotor/stator fault was electrical or mechanical (or not determined at all.)

There are a few forum members around who seem to have some real world expertise in mechatronics who could offer some insights into the possible causes. My real world background centres around big things, not little ones like DLSR's.

[c.a.m]

Another PF member reported a similar problem at the wide end of the Sigma 70-200 HSM II:

https://www.pentaxforums.com/forums/172-pentax-k-3/301756-my-ber-brief-k-3-ii...ml#post3341977

(post number 6)

Also see post number 8 in the same thread.

- Craig

[jawsy]

Another PF member reported a similar problem at the wide end of the Sigma 70-200 HSM II:

Well now you've done it. Guess what focal length my next shots will be from this lens!

[Craig66]

jawsy; CR didn't say, other than what's on invoice. The invoice say's, 065 Rotor, Stator ring, Dismantled lens to s/f new HSM focus motor assembly. Reassembled and checked.

tduell; No, after reading about the problems and affected serials on here, I contacted them, and was told, "Dear Customer, If you want send it, we will be happy to do the repair that is required. You need not send it now. In any case, this is a problem that we will repair under warranty. It did take a little emailing back and forth. When I pressed, what would happen out of warranty if it happen I got, Dear Craig, If your cameras exhibits this problem out of warranty, we will repair it at no charge.

c.a.m; Thanks for that link. I will send another email to CRK asking if they are aware of this Sigma firmware upgrade. As they are also the Sigma importers in Australia. Given that I did tell them in a note sent with the lens that they just repaired, that I was having the no auto focus at 70mm and up to about 75/80mm zoom setting. But was fine above that and up to 200mm. That they would/should have done that firmware upgrade. Clearly then weren't or didn't. As it's still doing it.

Now I don't know if I should be sending my K3-ll for checking, the lens, probably need to send both. Have to see what CRK say.


Thanks everyone for you input, help.