DA* 16-50mm: Thoughts on what I might be doing wrong.

Themdragons · 07-04-2016, 05:53 PM

I have a new K-3 and tried a new Pentax 16-50mm f/2.8 ED AL IF SDM SMC DA*lens in a store. Would not auto focus on my camera, nor would it focus with k-2s in the store, but it would work great with older Pentax K5 camera in store.
We cleaned contacts on all cameras and the lens and no change.
I realize this model isn't a brand "new" lens but it is still in the store in the box never really used more than held by customers, with all the parts present, wrapped in plastic.

fwbigd · 07-04-2016, 06:33 PM

This particular lens is noted for SDM failure. Mine failed three time before It was finally fixed under warranty. I would take it back and get your money back from the store. Many people modified the firmware so that the lens uses the screw drive vs the lens SDM drive.

Themdragons · 07-04-2016, 06:36 PM

I never bought it, I was trying it in the store before I bought it. It wasn't a named camera store, more of a big box store, thus the clerks couldn't help. Now I have to research what wide lens I'm going to buy in its place...

**jatrax** · 07-04-2016, 07:01 PM

As noted, this lens is prone to SDM failure. Some reports indicate that a long period of disuse is part of the cause for the failure, which might be a factor if this store has had it for a long time. That said, it is an excellent lens, when it works. Why it would function on one camera and not another is a bit mystifying. One thought I had was that there is a MF/AF switch on the lens, might be a long shot but it is possible this got bumped between cameras. Other than that, and cleaning the contacts, which you did I have no other advice.

If they are willing to sell it to you at a bargain price I would still consider it, just convert (or have it converted) to screwdrive. Mine was converted and I found it was actually faster that way.

The lens I replaced my 16-50 with is the DA 16-85. Quite a bit slower and if you really need f/2.8 then not an option but I found it to be a strong competitor for image quality at least within the zone I usually shoot at which is generally stopped down quite a bit. The extra reach was a benefit and I still use it on my k-3.

bar_foo · 07-04-2016, 09:43 PM - **1 Like**

Originally posted by jatrax

As noted, this lens is prone to SDM failure.

How can the lens working properly on the K5 be explained? If it was just SDM failure we would not expect it to work on any camera except an older screwdrive-only one.

**UncleVanya** · 07-04-2016, 11:20 PM

Originally posted by bar_foo

How can the lens working properly on the K5 be explained? If it was just SDM failure we would not expect it to work on any camera except an older screwdrive-only one.

Exactly. This is a bit weirder.

Blacknight659 · 07-05-2016, 10:01 AM

Working on another camera is a bit hard to explain. In my opinion, if you can exchange or return the lens I would do so. Otherwise, I can vouch for the SDM to Screw drive conversion. https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/321757-how-...ive-video.html

If you don't want the lens to be screwdrive and you are able to exchange/return, consider the 17-50 sigma and tamron. They are wonderful performers but you won't have the WR. Go for the 20-40 limited if you can work with the range and need the WR. If speed isn't an issue, the 16-85 WR is a great lens.

07-04-2016, 05:53 PM	#1
Themdragons New Member Join Date: Sep 2011 Location: East St. Paul Posts: 12	*DA 16-50mm: Thoughts on what I might be doing wrong.** I have a new K-3 and tried a new Pentax 16-50mm f/2.8 ED AL IF SDM SMC DA*lens in a store. Would not auto focus on my camera, nor would it focus with k-2s in the store, but it would work great with older Pentax K5 camera in store. We cleaned contacts on all cameras and the lens and no change. I realize this model isn't a brand "new" lens but it is still in the store in the box never really used more than held by customers, with all the parts present, wrapped in plastic.

07-04-2016, 06:36 PM	#3
Themdragons New Member Join Date: Sep 2011 Location: East St. Paul Posts: 12 Original Poster	I never bought it, I was trying it in the store before I bought it. It wasn't a named camera store, more of a big box store, thus the clerks couldn't help. Now I have to research what wide lens I'm going to buy in its place... Last edited by Themdragons; 07-04-2016 at 06:47 PM.

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07-04-2016, 06:33 PM	#2
fwbigd Veteran Member Join Date: Jun 2007 Location: Fort Worth TX Posts: 339	This particular lens is noted for SDM failure. Mine failed three time before It was finally fixed under warranty. I would take it back and get your money back from the store. Many people modified the firmware so that the lens uses the screw drive vs the lens SDM drive.

07-04-2016, 07:01 PM	#4
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	As noted, this lens is prone to SDM failure. Some reports indicate that a long period of disuse is part of the cause for the failure, which might be a factor if this store has had it for a long time. That said, it is an excellent lens, when it works. Why it would function on one camera and not another is a bit mystifying. One thought I had was that there is a MF/AF switch on the lens, might be a long shot but it is possible this got bumped between cameras. Other than that, and cleaning the contacts, which you did I have no other advice. If they are willing to sell it to you at a bargain price I would still consider it, just convert (or have it converted) to screwdrive. Mine was converted and I found it was actually faster that way. The lens I replaced my 16-50 with is the DA 16-85. Quite a bit slower and if you really need f/2.8 then not an option but I found it to be a strong competitor for image quality at least within the zone I usually shoot at which is generally stopped down quite a bit. The extra reach was a benefit and I still use it on my k-3.

07-04-2016, 09:43 PM - 1 Like	#5
bar_foo Senior Member Join Date: Feb 2014 Location: Vancouver, BC Posts: 108	Originally posted by jatrax As noted, this lens is prone to SDM failure. How can the lens working properly on the K5 be explained? If it was just SDM failure we would not expect it to work on any camera except an older screwdrive-only one.

07-04-2016, 11:20 PM	#6
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,454	Originally posted by bar_foo How can the lens working properly on the K5 be explained? If it was just SDM failure we would not expect it to work on any camera except an older screwdrive-only one. Exactly. This is a bit weirder.

07-05-2016, 10:01 AM	#7
Blacknight659 Veteran Member Join Date: Aug 2013 Photos: Gallery \| Albums Posts: 731	Working on another camera is a bit hard to explain. In my opinion, if you can exchange or return the lens I would do so. Otherwise, I can vouch for the SDM to Screw drive conversion. https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/321757-how-...ive-video.html If you don't want the lens to be screwdrive and you are able to exchange/return, consider the 17-50 sigma and tamron. They are wonderful performers but you won't have the WR. Go for the 20-40 limited if you can work with the range and need the WR. If speed isn't an issue, the 16-85 WR is a great lens.