21mm DA LTD - it came apart in my hand - twice!

mazugrin · 12-07-2014, 04:57 PM

I've had the SMC-DA 21mm f/3.2 AL Limited lens for a while. It's been a great lens, but I've recently had an experience that has left my confidence in the LTD lens' build quality a little bit shaken, and am wondering if others have experienced this: A few months ago, the lens effectively fell apart in my hands. While autofucusing, the front of the lens came off along with a collection of lens elements!

The lens is out of warranty, but I boxed it up carefully and sent it to Pentax for repair. I expected to eventually be contacted with an estimated cost of repair, but instead I received, after 3 or 4 weeks, the lens repaired for free. There was no explanation of why it was repaired without charge despite being out of warranty, but I wasn't complaining and was happy to have the lens back.

Unfortunately, a few months later, the same thing started to happen again. This time, I noticed it was happening before the lens came completely apart. The first symptom was that the lens was unable to focus to infinity, either via auto- or manual-focusing. I noticed that I could tighten the lens parts back together myself, so that's what I've been doing, rather than send it back to Pentax again and possibly be charged for a repair which may or may not stand the test of even a short time.

I also have the 31mm limited, but it's a much different design and has never given me any worries. But, I'm a little bit concerned with the prospect of spending money on other lenses that are similar to the 21mm - like the 15mm.

Has anyone else experienced this - or have I just been the unlucky one who by an unlucky fluke got a bad lens?

**sergysergy** · 12-07-2014, 05:17 PM

Apparently you are not alone:

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/183326-broken-21mm.html

manstanox · 12-07-2014, 05:42 PM

Exactly the same happened to me two weeks ago. Suddenly the lens - a DA 21mm Ltd - had trouble focussing and then the front of the lens just came off in my hand. It is not a new lens - in fact I had just purchased it through flea-bay. However, it was in normal, i.e. good, condition when I received it only to suddenly disintegrate. It is now being repaired and hopefully back in my hands this coming week.

**THoog** · 12-07-2014, 06:38 PM

Unfortunately, it is not uncommon for the DA21 (the SMC version, at least) - It's been dubbed "self-disassembly". I have not heard of similar issues with any of the other DA Ltds. Basically, the three screws that secure the front half of the lens (including the optics) break their Locktite seals and gradually work loose. So long as the AF electrical contact "comb" doesn't get broken, it's pretty easy to repair.

**Wingincamera** · 12-07-2014, 08:51 PM

I want to get a DA21, is there a way to check the screws & locktite seals? Maybe reapply the locktite?

**THoog** · 12-08-2014, 07:28 AM - **1 Like**

Originally posted by Wingincamera

I want to get a DA21, is there a way to check the screws & locktite seals? Maybe reapply the locktite?

See this post for pictures:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/121842-prob...ml#post1262737

1) Remove the hood.
2) Remove the center "beauty ring" - note that it does not include the plate with the name, specs, and serial number. It is actually held in place with double-side tape. Using a very small flat screwdriver, pry up around the edges of the optic (it can be done without touching the glass, just be careful). There is a second beauty ring with the name, etc., but it can be left where it is.
3) This will expose three cross-point screws. Remove these screws, and the front ring that the hood attaches to will come off.
4) This will expose the three problem screws. They are around the outer edge of the lens - it should not be necessary to touch any of the other screws. Check that the three outer screws are tight (but not too tight, or the lens won't be able to focus). Apply locktite.
5) Reverse steps 3-1.

If you have a lens that has come apart, the most important thing is do NOT bump or squash the brass AF contact "comb". It is frightfully easy to bend or break, and then the lens won't autofocus. If you bend a contact, Don't Panic! It should be possible to straighten it by squeezing gently between your fingers. Just go slow and be gentle. Getting the front half of the lens reinserted in the back half can be a little tricky because of the comb. Rather than inserting it straight in, you have to hook the piece with the comb into the back half of the lens, then jiggle the rest in place. I got most of the way there, then had to hold everything together in my left hand so that I could get at the rear of the lens and line up the aperture linkages with a small screwdriver.

lytrytyr · 12-08-2014, 11:05 AM

Originally posted by THoog

I have not heard of similar issues with any of the other DA Ltds.

A couple of years ago,
there was a thread on a French forum
about similar problems with the DA 40 Ltd.

---------- Post added 12-08-14 at 12:07 PM ----------

Originally posted by THoog

This will expose three cross-point screws.

Are those JIS?

**THoog** · 12-08-2014, 12:41 PM

Originally posted by lytrytyr

Are those JIS?

Probably.

Here's another thread with notes on how to put a DA21 back together:

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/249072-need...assembled.html

**Wingincamera** · 12-10-2014, 01:55 PM

Most of the talk here is about the SMC version of the 21mm. Would the HD version be the same?

**THoog** · 12-10-2014, 02:55 PM

Originally posted by Wingincamera

Most of the talk here is about the SMC version of the 21mm. Would the HD version be the same?

Don't know. The mechanical design is (probably) the same, but they may have modified the assembly process to address the problem. I haven't heard of any HD DA 21s coming apart, but there have not been enough of them in the field long enough for the screws to get loose.

There's always the possibility that the problem is due to a bad batch of locktite glue, or a bad choice of glue, or improper application of the glue. I don't think anyone has found a relationship between failures and serial numbers or manufacture dates.

timothy.malone · 12-11-2014, 07:21 AM

That's a shame. When I had this lens it was one of my favorites. I really loved the color.

Nicolas06 · 12-11-2014, 04:19 PM

Originally posted by Wingincamera

Most of the talk here is about the SMC version of the 21mm. Would the HD version be the same?

Apparently this is something that come after a few years... The HD version are arround 1 year in the market.

On the french forum apparently they also said you are more likely to get the problem if you put/remove a filter often.

**Wingincamera** · 12-11-2014, 08:21 PM

I will take a chance on the HD 21mm. That will complete my lens collection, I have the Pentax 15, 35 Macro, 50 Macro, 70, 18-135 and a Tammy 70-200mm.

**THoog** · 12-13-2014, 09:29 PM

Originally posted by Nicolas06

On the french forum apparently they also said you are more likely to get the problem if you put/remove a filter often.

That makes sense - because of the quick-shift design, if you are tightening / loosening a filter, then you probably have the focus ring against the near/far hard stop, and the torque is being exerted against the screws, cracking the locktite seals.

Originally posted by Wingincamera

I will take a chance on the HD 21mm. That will complete my lens collection,

Good choice - it's a great little lens!

12-07-2014, 04:57 PM	#1
mazugrin New Member Join Date: Apr 2010 Location: Boston Posts: 2	21mm DA LTD - it came apart in my hand - twice! I've had the SMC-DA 21mm f/3.2 AL Limited lens for a while. It's been a great lens, but I've recently had an experience that has left my confidence in the LTD lens' build quality a little bit shaken, and am wondering if others have experienced this: A few months ago, the lens effectively fell apart in my hands. While autofucusing, the front of the lens came off along with a collection of lens elements! The lens is out of warranty, but I boxed it up carefully and sent it to Pentax for repair. I expected to eventually be contacted with an estimated cost of repair, but instead I received, after 3 or 4 weeks, the lens repaired for free. There was no explanation of why it was repaired without charge despite being out of warranty, but I wasn't complaining and was happy to have the lens back. Unfortunately, a few months later, the same thing started to happen again. This time, I noticed it was happening before the lens came completely apart. The first symptom was that the lens was unable to focus to infinity, either via auto- or manual-focusing. I noticed that I could tighten the lens parts back together myself, so that's what I've been doing, rather than send it back to Pentax again and possibly be charged for a repair which may or may not stand the test of even a short time. I also have the 31mm limited, but it's a much different design and has never given me any worries. But, I'm a little bit concerned with the prospect of spending money on other lenses that are similar to the 21mm - like the 15mm. Has anyone else experienced this - or have I just been the unlucky one who by an unlucky fluke got a bad lens?

12-07-2014, 05:42 PM	#3
manstanox Junior Member Join Date: Oct 2012 Location: High Wycombe Photos: Gallery Posts: 35	broken 21mm Exactly the same happened to me two weeks ago. Suddenly the lens - a DA 21mm Ltd - had trouble focussing and then the front of the lens just came off in my hand. It is not a new lens - in fact I had just purchased it through flea-bay. However, it was in normal, i.e. good, condition when I received it only to suddenly disintegrate. It is now being repaired and hopefully back in my hands this coming week.

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12-07-2014, 05:17 PM	#2
sergysergy Site Supporter Join Date: Jan 2011 Photos: Gallery Posts: 5,170	Apparently you are not alone: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/183326-broken-21mm.html

12-07-2014, 06:38 PM	#4
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	Unfortunately, it is not uncommon for the DA21 (the SMC version, at least) - It's been dubbed "self-disassembly". I have not heard of similar issues with any of the other DA Ltds. Basically, the three screws that secure the front half of the lens (including the optics) break their Locktite seals and gradually work loose. So long as the AF electrical contact "comb" doesn't get broken, it's pretty easy to repair.

12-07-2014, 08:51 PM	#5
Wingincamera Loyal Site Supporter Join Date: Oct 2012 Location: Pine Haven, Wyoming Photos: Gallery \| Albums Posts: 1,182	I want to get a DA21, is there a way to check the screws & locktite seals? Maybe reapply the locktite?

12-08-2014, 07:28 AM - 1 Like	#6
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	Originally posted by Wingincamera I want to get a DA21, is there a way to check the screws & locktite seals? Maybe reapply the locktite? See this post for pictures: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/121842-prob...ml#post1262737 1) Remove the hood. 2) Remove the center "beauty ring" - note that it does not include the plate with the name, specs, and serial number. It is actually held in place with double-side tape. Using a very small flat screwdriver, pry up around the edges of the optic (it can be done without touching the glass, just be careful). There is a second beauty ring with the name, etc., but it can be left where it is. 3) This will expose three cross-point screws. Remove these screws, and the front ring that the hood attaches to will come off. 4) This will expose the three problem screws. They are around the outer edge of the lens - it should not be necessary to touch any of the other screws. Check that the three outer screws are tight (but not too tight, or the lens won't be able to focus). Apply locktite. 5) Reverse steps 3-1. If you have a lens that has come apart, the most important thing is do NOT bump or squash the brass AF contact "comb". It is frightfully easy to bend or break, and then the lens won't autofocus. If you bend a contact, Don't Panic! It should be possible to straighten it by squeezing gently between your fingers. Just go slow and be gentle. Getting the front half of the lens reinserted in the back half can be a little tricky because of the comb. Rather than inserting it straight in, you have to hook the piece with the comb into the back half of the lens, then jiggle the rest in place. I got most of the way there, then had to hold everything together in my left hand so that I could get at the rear of the lens and line up the aperture linkages with a small screwdriver.

12-08-2014, 11:05 AM	#7
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by THoog I have not heard of similar issues with any of the other DA Ltds. A couple of years ago, there was a thread on a French forum about similar problems with the DA 40 Ltd. ---------- Post added 12-08-14 at 12:07 PM ---------- Originally posted by THoog This will expose three cross-point screws. Are those JIS?

12-08-2014, 12:41 PM	#8
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	Originally posted by lytrytyr Are those JIS? Probably. Here's another thread with notes on how to put a DA21 back together: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/249072-need...assembled.html

12-10-2014, 01:55 PM	#9
Wingincamera Loyal Site Supporter Join Date: Oct 2012 Location: Pine Haven, Wyoming Photos: Gallery \| Albums Posts: 1,182	Most of the talk here is about the SMC version of the 21mm. Would the HD version be the same?

12-10-2014, 02:55 PM	#10
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	Originally posted by Wingincamera Most of the talk here is about the SMC version of the 21mm. Would the HD version be the same? Don't know. The mechanical design is (probably) the same, but they may have modified the assembly process to address the problem. I haven't heard of any HD DA 21s coming apart, but there have not been enough of them in the field long enough for the screws to get loose. There's always the possibility that the problem is due to a bad batch of locktite glue, or a bad choice of glue, or improper application of the glue. I don't think anyone has found a relationship between failures and serial numbers or manufacture dates.

12-11-2014, 07:21 AM	#11
timothy.malone New Member Join Date: May 2010 Location: Upstate NY Posts: 8	That's a shame. When I had this lens it was one of my favorites. I really loved the color.

12-11-2014, 04:19 PM	#12
Nicolas06 Veteran Member Join Date: Nov 2013 Posts: 4,854	Originally posted by Wingincamera Most of the talk here is about the SMC version of the 21mm. Would the HD version be the same? Apparently this is something that come after a few years... The HD version are arround 1 year in the market. On the french forum apparently they also said you are more likely to get the problem if you put/remove a filter often.

12-11-2014, 08:21 PM	#13
Wingincamera Loyal Site Supporter Join Date: Oct 2012 Location: Pine Haven, Wyoming Photos: Gallery \| Albums Posts: 1,182	I will take a chance on the HD 21mm. That will complete my lens collection, I have the Pentax 15, 35 Macro, 50 Macro, 70, 18-135 and a Tammy 70-200mm.

12-13-2014, 09:29 PM	#14
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	Originally posted by Nicolas06 On the french forum apparently they also said you are more likely to get the problem if you put/remove a filter often. That makes sense - because of the quick-shift design, if you are tightening / loosening a filter, then you probably have the focus ring against the near/far hard stop, and the torque is being exerted against the screws, cracking the locktite seals. Originally posted by Wingincamera I will take a chance on the HD 21mm. That will complete my lens collection, Good choice - it's a great little lens!