Stuck aperture on Pentax DA 16-85

RobG · 03-28-2020, 06:28 AM

I'm very upset to find that all the photos I took today are ruined. It looks like the aperture on the HDDA 16-85 is stuck wide open. Almost every photo is overexposed despite the camera being set to -0.5EV. Photos with the DFA 150-450 are fine, so it seems to be the 16-85 which has the problem. Has anyone experienced this with the 16-85? I just tried my 100 macro and it's fine. Using DOF preview on the 16-85 has no effect, although if I manually move the aperture mechanism, the iris does move, so it seems that the actuator isn't working.

Stuck aperture by RobGeraghty, on Flickr

**jlstrawman** · 03-28-2020, 07:36 AM

Dirty or misaligned contact?

bertwert · 03-28-2020, 07:50 AM

Originally posted by jlstrawman

Dirty or misaligned contact?

That's my first thought... clean contacts on camera and lens.

Also, have you got another body to try it on?

**Just1MoreDave** · 03-28-2020, 08:37 AM

Another idea is the aperture lever is bent, so the arm in the camera can't engage it. Compare it to other lenses. The camera would only make the actuator arm noise when using DOF preview, so it would be much quieter.

Thagomizer · 03-28-2020, 11:32 AM

I actually had this same problem. Fortunately the lens was still under warranty, so I was able to get it fixed at no charge.

jim.haase · 03-28-2020, 01:23 PM

Had the same problem. It happenned when I tripped and fell. Camera or lens did not hit the ground but I guess it jarred it enough the the aperture was stuck wide open. Sent it to Advance Camera in Portland and they repaired it for what I thought was a very reasonable price. I believe around $75.

RobG · 03-28-2020, 04:58 PM

Originally posted by jlstrawman

Dirty or misaligned contact?

Originally posted by bertwert

That's my first thought... clean contacts on camera and lens.

Also, have you got another body to try it on?

Any idea which contact(s) connect with aperture operation?

RobG · 03-28-2020, 07:47 PM

Thanks for the suggestions everyone. It looks like the return spring on the aperture is broken. I just did a comparison test with the Tamron 17-50 and the Tamron lens is fine, so hopefully the camera is also fine. I know I've used the 16-85 a lot in the last 15 months, but I've used the Tamron a lot more, and it's aprture spring is fine, despite being a much cheaper lens. The Tamron does have an electronic fault, but it was an import from Hong Kong so no chance of fixing it when it was under warranty. Looks like I'll have to go back to the Tamron lens for a while. Next I have to decide whether to drive back to Mount Coree again to take the photos from yesterday all over again...

noelpolar · 03-28-2020, 08:06 PM

FWIW my sigma 70-200 did the same thing.... I checked to see if the aperture lever was bent and binding.... no go.... so I took it to CR Kennedy.... about a $130 repair late last year.

When in China many years ago I dropped my K5II and all lenses shot wide open from that point on... a connector inside the camera had come off.

RobG · 03-29-2020, 04:40 AM

Originally posted by noelpolar

FWIW my sigma 70-200 did the same thing.... I checked to see if the aperture lever was bent and binding.... no go.... so I took it to CR Kennedy.... about a $130 repair late last year.
When in China many years ago I dropped my K5II and all lenses shot wide open from that point on... a connector inside the camera had come off.

Thanks Noel. I'm just disappointed that this has happened to a lens which is only just over a year old, while I have other lenses much older which are going strong. I didn't drop the lens. Anyway, I've emailed CRK so hopefully I'll get some guidance tomorrow.

---------- Post added 29-03-20 at 11:12 PM ----------

FWIW this is (almost) what I wanted to photograph yesterday.

The corner of the Territory by RobGeraghty, on Flickr

I say almost, because I didn't walk the last 200m to the top of the peak when I went back today, because there was a lot more cloud.

TerryL · 03-29-2020, 12:25 PM

Originally posted by RobG

Thanks Noel. I'm just disappointed that this has happened to a lens which is only just over a year old, while I have other lenses much older which are going strong. I didn't drop the lens. Anyway, I've emailed CRK so hopefully I'll get some guidance tomorrow.

---------- Post added 29-03-20 at 11:12 PM ----------

FWIW this is (almost) what I wanted to photograph yesterday.

The corner of the Territory by RobGeraghty, on Flickr

I say almost, because I didn't walk the last 200m to the top of the peak when I went back today, because there was a lot more cloud.

Beautiful photo.

stevebrot · 03-29-2020, 12:31 PM

Originally posted by RobG

Thanks Noel. I'm just disappointed that this has happened to a lens which is only just over a year old, while I have other lenses much older which are going strong. I didn't drop the lens. Anyway, I've emailed CRK so hopefully I'll get some guidance tomorrow.

With any luck they will repair it under warranty, given you are only a little beyond a year.

Steve

RobG · 03-29-2020, 05:08 PM

Originally posted by TerryL

Beautiful photo.

Thanks! I'll have to be satisfied with the other cameras for the previous day. The only vaguely successful Pentax shots from Saturday were with the Theta V.

Originally posted by stevebrot

With any luck they will repair it under warranty, given you are only a little beyond a year.

I hope so, Steve!

DaveD · 11-21-2022, 04:41 AM - **3 Likes**

Hi, I know this is a bit late compared to the original post, but I also had a problem with the DA 16-85 sticking in open aperture.

As the lens was out of warranty I took it apart myself and it turned out that the spring had come unhooked from its pin so the aperture could no longer be changed. The pin is quite short and there is nothing to stop the spring from sliding off the top. My solution was to replace the spring on the pin (not easy as it is tiny) and put a tiny amount of glue on the pin to stop it sliding off.
However I do not suggest that anyone tries to do this themselves as there are some very small parts that are easily lost, so get it fixed professionally instead.

I hope this may help with anyone else who has this problem.

RobG · 11-21-2022, 04:48 AM

Originally posted by DaveD

As the lens was out of warranty I took it apart myself and it turned out that the spring had come unhooked from its pin so the aperture could no longer be changed. The pin is quite short and there is nothing to stop the spring from sliding off the top. My solution was to replace the spring on the pin (not easy as it is tiny) and put a tiny amount of glue on the pin to stop it sliding off.
However I do not suggest that anyone tries to do this themselves as there are some very small parts that are easily lost, so get it fixed professionally instead.
I hope this may help with anyone else who has this problem.

Good to know! I gather that mine had that issue. It was fixed under warranty.

03-28-2020, 06:28 AM	#1
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,888	Stuck aperture on Pentax DA 16-85 I'm very upset to find that all the photos I took today are ruined. It looks like the aperture on the HDDA 16-85 is stuck wide open. Almost every photo is overexposed despite the camera being set to -0.5EV. Photos with the DFA 150-450 are fine, so it seems to be the 16-85 which has the problem. Has anyone experienced this with the 16-85? I just tried my 100 macro and it's fine. Using DOF preview on the 16-85 has no effect, although if I manually move the aperture mechanism, the iris does move, so it seems that the actuator isn't working. Stuck aperture by RobGeraghty, on Flickr

03-28-2020, 08:06 PM	#9
noelpolar Veteran Member Join Date: Oct 2013 Location: Goolwa, SA Photos: Gallery Posts: 4,310	FWIW my sigma 70-200 did the same thing.... I checked to see if the aperture lever was bent and binding.... no go.... so I took it to CR Kennedy.... about a $130 repair late last year. When in China many years ago I dropped my K5II and all lenses shot wide open from that point on... a connector inside the camera had come off. Last edited by noelpolar; 03-28-2020 at 08:14 PM.

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03-28-2020, 07:36 AM	#2
jlstrawman Site Supporter Join Date: Feb 2010 Location: Midwest US Photos: Gallery Posts: 1,058	Dirty or misaligned contact?

03-28-2020, 07:50 AM	#3
bertwert Veteran Member Join Date: Jun 2015 Location: Golden, BC Posts: 15,173	Originally posted by jlstrawman Dirty or misaligned contact? That's my first thought... clean contacts on camera and lens. Also, have you got another body to try it on?

03-28-2020, 08:37 AM	#4
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	Another idea is the aperture lever is bent, so the arm in the camera can't engage it. Compare it to other lenses. The camera would only make the actuator arm noise when using DOF preview, so it would be much quieter.

03-28-2020, 11:32 AM	#5
Thagomizer Pentaxian Join Date: Jun 2014 Location: London Ontario Posts: 2,068	I actually had this same problem. Fortunately the lens was still under warranty, so I was able to get it fixed at no charge.

03-28-2020, 01:23 PM	#6
jim.haase Forum Member Join Date: Jan 2011 Photos: Gallery \| Albums Posts: 67	Had the same problem. It happenned when I tripped and fell. Camera or lens did not hit the ground but I guess it jarred it enough the the aperture was stuck wide open. Sent it to Advance Camera in Portland and they repaired it for what I thought was a very reasonable price. I believe around $75.

03-28-2020, 04:58 PM	#7
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,888 Original Poster	Originally posted by jlstrawman Dirty or misaligned contact? Originally posted by bertwert That's my first thought... clean contacts on camera and lens. Also, have you got another body to try it on? Any idea which contact(s) connect with aperture operation?

03-28-2020, 07:47 PM	#8
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,888 Original Poster	Thanks for the suggestions everyone. It looks like the return spring on the aperture is broken. I just did a comparison test with the Tamron 17-50 and the Tamron lens is fine, so hopefully the camera is also fine. I know I've used the 16-85 a lot in the last 15 months, but I've used the Tamron a lot more, and it's aprture spring is fine, despite being a much cheaper lens. The Tamron does have an electronic fault, but it was an import from Hong Kong so no chance of fixing it when it was under warranty. Looks like I'll have to go back to the Tamron lens for a while. Next I have to decide whether to drive back to Mount Coree again to take the photos from yesterday all over again...

03-29-2020, 04:40 AM	#10
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,888 Original Poster	Originally posted by noelpolar FWIW my sigma 70-200 did the same thing.... I checked to see if the aperture lever was bent and binding.... no go.... so I took it to CR Kennedy.... about a $130 repair late last year. When in China many years ago I dropped my K5II and all lenses shot wide open from that point on... a connector inside the camera had come off. Thanks Noel. I'm just disappointed that this has happened to a lens which is only just over a year old, while I have other lenses much older which are going strong. I didn't drop the lens. Anyway, I've emailed CRK so hopefully I'll get some guidance tomorrow. ---------- Post added 29-03-20 at 11:12 PM ---------- FWIW this is (almost) what I wanted to photograph yesterday. The corner of the Territory by RobGeraghty, on Flickr I say almost, because I didn't walk the last 200m to the top of the peak when I went back today, because there was a lot more cloud.

03-29-2020, 12:25 PM	#11
TerryL Pentaxian Join Date: Jan 2018 Location: Virginia, USA Photos: Albums Posts: 850	Originally posted by RobG Thanks Noel. I'm just disappointed that this has happened to a lens which is only just over a year old, while I have other lenses much older which are going strong. I didn't drop the lens. Anyway, I've emailed CRK so hopefully I'll get some guidance tomorrow. ---------- Post added 29-03-20 at 11:12 PM ---------- FWIW this is (almost) what I wanted to photograph yesterday. The corner of the Territory by RobGeraghty, on Flickr I say almost, because I didn't walk the last 200m to the top of the peak when I went back today, because there was a lot more cloud. Beautiful photo.

03-29-2020, 12:31 PM	#12
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by RobG Thanks Noel. I'm just disappointed that this has happened to a lens which is only just over a year old, while I have other lenses much older which are going strong. I didn't drop the lens. Anyway, I've emailed CRK so hopefully I'll get some guidance tomorrow. With any luck they will repair it under warranty, given you are only a little beyond a year. Steve

03-29-2020, 05:08 PM	#13
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,888 Original Poster	Originally posted by TerryL Beautiful photo. Thanks! I'll have to be satisfied with the other cameras for the previous day. The only vaguely successful Pentax shots from Saturday were with the Theta V. Originally posted by stevebrot With any luck they will repair it under warranty, given you are only a little beyond a year. I hope so, Steve!

11-21-2022, 04:41 AM - 3 Likes	#14
DaveD New Member Join Date: Nov 2022 Posts: 1	Hi, I know this is a bit late compared to the original post, but I also had a problem with the DA 16-85 sticking in open aperture. As the lens was out of warranty I took it apart myself and it turned out that the spring had come unhooked from its pin so the aperture could no longer be changed. The pin is quite short and there is nothing to stop the spring from sliding off the top. My solution was to replace the spring on the pin (not easy as it is tiny) and put a tiny amount of glue on the pin to stop it sliding off. However I do not suggest that anyone tries to do this themselves as there are some very small parts that are easily lost, so get it fixed professionally instead. I hope this may help with anyone else who has this problem.

11-21-2022, 04:48 AM	#15
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,888 Original Poster	Originally posted by DaveD As the lens was out of warranty I took it apart myself and it turned out that the spring had come unhooked from its pin so the aperture could no longer be changed. The pin is quite short and there is nothing to stop the spring from sliding off the top. My solution was to replace the spring on the pin (not easy as it is tiny) and put a tiny amount of glue on the pin to stop it sliding off. However I do not suggest that anyone tries to do this themselves as there are some very small parts that are easily lost, so get it fixed professionally instead. I hope this may help with anyone else who has this problem. Good to know! I gather that mine had that issue. It was fixed under warranty.