Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-13-2020, 01:38 PM   #1
New Member




Join Date: Jul 2019
Photos: Albums
Posts: 15
DA* 2.8/16-50 Front Wobble

Hello,

I recently purchased a used copy of the DA* 2.8/16-50 and noticed that the front of the lens has considerable play when fully retracted at 16mm. The wobble is basically absent throughout the rest of the zoom range---there is practically no play past about 18 all the way to 50mm. It is also independent of focus distance choice. Otherwise, the lens is in a good condition with the SDM working properly, no signs of impact, or other evident problems.

Can other owners of this lens comment if this behavior is common/normal, or if it may be a sign of excessive force applied as some point (perhaps when mounting the hood or a filter)?

I can still return the lens to the seller, but would appreciate feedback from Forum members before deciding what to do next.

Thank you,

04-13-2020, 01:45 PM   #2
Site Supporter
Site Supporter
sergysergy's Avatar

Join Date: Jan 2011
Posts: 4,020
Hi, I have had 2 copies of this lens and both of them had it. I never felt it was a problem but if you don't feel comfortable with you should return it.
04-13-2020, 02:30 PM   #3
Loyal Site Supporter
Loyal Site Supporter
blackcloudbrew's Avatar

Join Date: Mar 2009
Location: Cotati, California USA
Photos: Gallery | Albums
Posts: 4,300
Yep, mine too for 12 years. No problem. I will also say that I know I've seen a number of posts about this very thing on this site over the years.
04-13-2020, 02:38 PM   #4
sjp
New Member




Join Date: Jul 2019
Photos: Albums
Posts: 15
Original Poster
I'm perfectly OK with the behavior if that is what others have experienced with their copies. Thank you both for responding.

04-13-2020, 09:48 PM   #5
Senior Member




Join Date: Jan 2013
Posts: 290
...

I almost bought a copy of this lens. Wobbling at 16mm was an issue for me, the front element was even moving forward and backward - the lens was so much softer in one of those extreme positions to become unreliable for me.
04-14-2020, 12:56 AM   #6
Site Supporter
Site Supporter
microlight's Avatar

Join Date: Sep 2011
Location: Hampshire, UK
Posts: 1,679
The older 16-45 also wobbles a little at full extension (16mm), but thatís not a real problem either.
04-14-2020, 04:56 AM   #7
Pentaxian
rogerstg's Avatar

Join Date: Oct 2007
Location: Rhode Island
Photos: Albums
Posts: 836
I've used this lens for a dozen years and it's always performed very well: my most used lens. Still, prompted by this thread, I checked it and notice some play in the area of the front element. It was most at 16mm, but was present throughout the focal range.

I recently tested this lens for de-centering and front/back focus and found no problems. Images are tack sharp. You should let the lens' performance be your guide.

Last edited by rogerstg; 04-14-2020 at 05:05 AM.
04-14-2020, 06:21 AM   #8
Senior Member




Join Date: Jan 2010
Location: Netherlands
Photos: Gallery
Posts: 198
I have the same experience with the DA* 60-250 but also see no problems in it's performance.

04-14-2020, 07:40 AM   #9
sjp
New Member




Join Date: Jul 2019
Photos: Albums
Posts: 15
Original Poster
Are those of you whose lenses show more play at the extreme end(s) able to see the impact in the viewfinder? At 16mm, I can easily lift the very front of the lens with the tip of my finger and can see the composition change very slightly. There is not enough play past 18mm for me to notice any difference, if I try pushing the front up. I also have the 4/16-45 and a few other zooms and have never experienced anything like this with any of them.

I hope to do more comprehensive testing over the weekend and report back. I will try to share a video, if I can figure out how to do that.
04-15-2020, 12:14 PM   #10
Senior Member




Join Date: Jan 2010
Location: Netherlands
Photos: Gallery
Posts: 198
The wobble of my DA* 60-250 is at the extreme end maybe a tenth of a millimeter, hardly noticeable but you can just feel it in you're fingertips when trying to wobble it. My DA* 16-50 has much more wobble, maybe half of a millimeter. When looking trough the viewfinder and wobbling it, it is very hard to keep you're camera in a static position. But when i try to keep the guidelines in the viewfinder at a fixed position, i still can't notice any formation in the image.
I guess technically there should be a formation because the wobble also causes the front element to wobble.
04-15-2020, 07:49 PM   #11
sjp
New Member




Join Date: Jul 2019
Photos: Albums
Posts: 15
Original Poster
Hi all,

I just watched a very informative youtube video on the repair of the 2.8/16-50 with a focus problem (link below). Right at the start, around the 18 sec. mark, you can see the repairman grab the front of the lens and wobble it with ease. The copy I have is not quite as bad, but definitely shows the same symptoms. He then proceeds to basically completely disassemble the lens (from the mount down) to replace a plastic ring near the front. After reassembling the lens, he tests the front again, at around the 16:06 minute mark, and, although he does not spend much time on this test, you can still see that the front hardly moves at all after the repair.

I will do a few more image tests, but I think I will end up returning the lens. The video makes it pretty clear that the front ring in 'my' copy of the lens has been damaged, and think that it's just a matter of time before it fails completely. Given the amount of effort it takes to repair this type of damage, I can't imagine that having the repair done by an authorized repair place in the US would be economical given the price I paid.

The repair video is called "How to repair Pentax lens SMC DA* 16-50mm F2.8 ED AL [IF] SDM with focus problem" by DIGI SERVICE.


Last edited by sjp; 04-15-2020 at 07:52 PM. Reason: HTML link not shown properly
04-16-2020, 10:48 AM   #12
Senior Member




Join Date: Jan 2010
Location: Netherlands
Photos: Gallery
Posts: 198
Looks a lot like the wobble with my lens. Now i know what the reason is, a worn down rib inside the lens. I don't think it is a problem tough till it is totally worn down and the lens stops operating.
I don't know what the repair costs could be, so i just keep on using "a lens with a wobble" :-)
04-16-2020, 01:53 PM   #13
sjp
New Member




Join Date: Jul 2019
Photos: Albums
Posts: 15
Original Poster
If I bought the lens new, and it developed the wobble over time, I would probably just end up using it anyway like you. But I bought it used, and the front element moves upward nearly two mm, as measured on a ruler with the lens sitting on its cap. That's also how far the top of the front element drops with the lens mounted on the camera and held horizontally. So I think I will just cut my losses early and return it, but I still plan to do some tests before making my final decision.

Last edited by sjp; 04-16-2020 at 02:00 PM. Reason: Minor corrections
04-16-2020, 06:32 PM   #14
Pentaxian
rogerstg's Avatar

Join Date: Oct 2007
Location: Rhode Island
Photos: Albums
Posts: 836
QuoteOriginally posted by sjp Quote
the front element moves upward nearly two mm
That does seem like a lot.
04-17-2020, 12:13 PM   #15
Senior Member




Join Date: Jan 2010
Location: Netherlands
Photos: Gallery
Posts: 198
QuoteOriginally posted by sjp Quote
If I bought the lens new, and it developed the wobble over time, I would probably just end up using it anyway like you. But I bought it used, and the front element moves upward nearly two mm, as measured on a ruler with the lens sitting on its cap. That's also how far the top of the front element drops with the lens mounted on the camera and held horizontally. So I think I will just cut my losses early and return it, but I still plan to do some tests before making my final decision.
Don't understand me wrong, if i just bought the lens i would intermediately return it to.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, da*, da* 2.8/16-50, da* 2.8/16-50 front, front, front wobble, lens, pentax help, photography, play, troubleshooting, wobble
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
FA35/2 front element wobble DSLRnovice Pentax SLR Lens Discussion 9 05-24-2018 04:31 PM
DA 16-85 Lens Wobble / Creep Echo Eric Pentax SLR Lens Discussion 2 02-12-2018 03:36 AM
18-55 WR front wobble. Is this normal? sarge Pentax SLR Lens Discussion 9 09-05-2016 05:28 AM
measuring DA 16-45mm barrel wobble tibbitts Pentax SLR Lens Discussion 7 02-24-2014 09:38 AM
Shootout #2 - DA 15 Ltd / Tamron 17-50 @17 / DA* 16-50 @16 / Sigma 10-20 @16 EarlVonTapia Pentax SLR Lens Discussion 4 06-23-2013 10:17 PM



All times are GMT -7. The time now is 01:40 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top