16-85mm wr lens - slightly irregular resistance on zooming?

c_j_m · 10-17-2016, 04:29 PM

Recently bought the Pentax 16-85mm wr lens. Not used much so far, but I noticed immediately that there's a slight tug at certain points of the zoom range. At first, it was when just starting to extend the lens - a tug which then disappeared after use (break in perhaps?). I guessed it might be the seals offering some resistance. That seems to have gone with use, as I say, but at the other end of the zoom range when about fully extended, there's sometimes a similar effect. It's fairly subtle and doesn't interfere with use, but it's irritating given that I've not noticed this with other lenses I own. In other respects, the lens seems to work fine. I'd just like to make sure this is normal/within spec. I contacted Pentax direct and they suggested I go to a local dealer to try another example of the same lens to see if its consistent. For now, I'd appreciate if anyone can say how their own copy of this lens is. Does it display completely smooth/consistent resistance when zooming or are there, as with mine, moments when it has some extra resistance? I have seen reference somewhere to a vacuum type of resistance to certain weather seal lenses in use. Could it just be this?

I got the lens for a decent price from Amazon Warehouse and can return it if I'm not happy, but I need to make a decision soon. Sometimes other things I've bought from the warehouse have looked like new but have had issues which might have prompted the original buyer to return it. I'm wondering if this lens is such an example if the tug on the zoom movement is unusual.

thanks

**Quartermaster James** · 10-17-2016, 04:38 PM

Check to make sure that the seal isn't catching on the lip as the lens first extends. Mine did that. The adhesive was the problem. That said, at the far end of the zoom range mine also feels slightly stiffer for the last 5-15mm or so.

timb64 · 10-17-2016, 05:11 PM

Mine zooms smoothly through the full range.

c_j_m · 10-18-2016, 04:02 AM

The fact that yours, Tim, is smooth throughout suggests to me variability in quality control, at least. Will give the lens a last try, but likely I'll return it to Amazon. Don't mind quirkiness, but, with me, this'll become a niggle :-(

thanks for the help

timb64 · 10-18-2016, 05:41 AM

Originally posted by c_j_m

The fact that yours, Tim, is smooth throughout suggests to me variability in quality control, at least. Will give the lens a last try, but likely I'll return it to Amazon. Don't mind quirkiness, but, with me, this'll become a niggle :-(

thanks for the help

I am aware that others have also experienced a problem with slight decentring of some copies further suggesting quality control is not what it should be. A great shame as the IQ from the lens is very pleasing if you get a decent copy.Post some of your results, good or bad (!) here:

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/301618-da-1...at-can-do.html

**Quartermaster James** · 10-18-2016, 07:35 AM

Originally posted by c_j_m

The fact that yours, Tim, is smooth throughout suggests to me variability in quality control, at least. Will give the lens a last try, but likely I'll return it to Amazon. Don't mind quirkiness, but, with me, this'll become a niggle :-(

thanks for the help

Take some test shots and check the IQ.

c_j_m · 10-24-2016, 04:17 PM

Just to update what I've decided. Taken some more test photos with lens on trip to Cambridge which I've posted in the thread suggested by Tim. I like the range of focal lengths with this lens - particularly the wide end - but the catching of the zoom still bugs me. I'm sure now it is the weather sealing that causes this and it hasn't disappeared completely with more use. I find my copy of the lens quite sharp but haven't carried out a detailed analysis, just my simple reaction to what it's done for me. I've finally decided to return it. I've been using a few manual lenses recently and this Pentax zoom surprises with its lack of a similar quality feel. Its plastic body coupled with the zoom issue doesn't scream quality for me. Importantly, I've not been bowled over by the quality of capture managed. Given the quality control issues, maybe the optical performance of my copy isn't as good as the best.

10-17-2016, 04:29 PM	#1
c_j_m New Member Join Date: Aug 2016 Posts: 17	16-85mm wr lens - slightly irregular resistance on zooming? Recently bought the Pentax 16-85mm wr lens. Not used much so far, but I noticed immediately that there's a slight tug at certain points of the zoom range. At first, it was when just starting to extend the lens - a tug which then disappeared after use (break in perhaps?). I guessed it might be the seals offering some resistance. That seems to have gone with use, as I say, but at the other end of the zoom range when about fully extended, there's sometimes a similar effect. It's fairly subtle and doesn't interfere with use, but it's irritating given that I've not noticed this with other lenses I own. In other respects, the lens seems to work fine. I'd just like to make sure this is normal/within spec. I contacted Pentax direct and they suggested I go to a local dealer to try another example of the same lens to see if its consistent. For now, I'd appreciate if anyone can say how their own copy of this lens is. Does it display completely smooth/consistent resistance when zooming or are there, as with mine, moments when it has some extra resistance? I have seen reference somewhere to a vacuum type of resistance to certain weather seal lenses in use. Could it just be this? I got the lens for a decent price from Amazon Warehouse and can return it if I'm not happy, but I need to make a decision soon. Sometimes other things I've bought from the warehouse have looked like new but have had issues which might have prompted the original buyer to return it. I'm wondering if this lens is such an example if the tug on the zoom movement is unusual. thanks

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10-17-2016, 04:38 PM	#2
Quartermaster James Loyal Site Supporter Join Date: Oct 2014 Location: Anchorage, Alaska Posts: 653	Check to make sure that the seal isn't catching on the lip as the lens first extends. Mine did that. The adhesive was the problem. That said, at the far end of the zoom range mine also feels slightly stiffer for the last 5-15mm or so.

10-17-2016, 05:11 PM	#3
timb64 Pentaxian Join Date: Apr 2012 Location: /Situation : Doing my best to avoid idiots! Photos: Gallery Posts: 9,514	Mine zooms smoothly through the full range.

10-18-2016, 04:02 AM	#4
c_j_m New Member Join Date: Aug 2016 Posts: 17 Original Poster	The fact that yours, Tim, is smooth throughout suggests to me variability in quality control, at least. Will give the lens a last try, but likely I'll return it to Amazon. Don't mind quirkiness, but, with me, this'll become a niggle :-( thanks for the help

10-18-2016, 05:41 AM	#5
timb64 Pentaxian Join Date: Apr 2012 Location: /Situation : Doing my best to avoid idiots! Photos: Gallery Posts: 9,514	Originally posted by c_j_m The fact that yours, Tim, is smooth throughout suggests to me variability in quality control, at least. Will give the lens a last try, but likely I'll return it to Amazon. Don't mind quirkiness, but, with me, this'll become a niggle :-( thanks for the help I am aware that others have also experienced a problem with slight decentring of some copies further suggesting quality control is not what it should be. A great shame as the IQ from the lens is very pleasing if you get a decent copy.Post some of your results, good or bad (!) here: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/301618-da-1...at-can-do.html

10-18-2016, 07:35 AM	#6
Quartermaster James Loyal Site Supporter Join Date: Oct 2014 Location: Anchorage, Alaska Posts: 653	Originally posted by c_j_m The fact that yours, Tim, is smooth throughout suggests to me variability in quality control, at least. Will give the lens a last try, but likely I'll return it to Amazon. Don't mind quirkiness, but, with me, this'll become a niggle :-( thanks for the help Take some test shots and check the IQ.

10-24-2016, 04:17 PM	#7
c_j_m New Member Join Date: Aug 2016 Posts: 17 Original Poster	Just to update what I've decided. Taken some more test photos with lens on trip to Cambridge which I've posted in the thread suggested by Tim. I like the range of focal lengths with this lens - particularly the wide end - but the catching of the zoom still bugs me. I'm sure now it is the weather sealing that causes this and it hasn't disappeared completely with more use. I find my copy of the lens quite sharp but haven't carried out a detailed analysis, just my simple reaction to what it's done for me. I've finally decided to return it. I've been using a few manual lenses recently and this Pentax zoom surprises with its lack of a similar quality feel. Its plastic body coupled with the zoom issue doesn't scream quality for me. Importantly, I've not been bowled over by the quality of capture managed. Given the quality control issues, maybe the optical performance of my copy isn't as good as the best.