DA 17-70 f4 focus

Murra54 · 02-07-2016, 02:21 AM

I have been experiencing all the difficulties that other people have reported with the focusing at the longer end of this lens.

i was out using this lens, I like the range, three days ago and I have only just realised that I did not experience any of the normal
hunting and stopping of previous experience. The only difference was that I was trying an inexpensive circular polariser earlier in the day and had not remove it.

I just did a quick test in the back yard with polariser on and with it off and found that the lens focuses much better with the polariser on than it does with it off.

Not very technical I know.

has anyone else had this happen? I don't really want to replace this lens as it is my walk around.

HYS · 02-07-2016, 02:50 AM

Change the SDM motor. It starts in this way. I had the chance to experience this feelings up to full stopping to focus.
Now my 17-70 works fine. A smile for some $100

but what to do!

starbase218 · 02-07-2016, 05:01 AM

Originally posted by HYS

Change the SDM motor. It starts in this way. I had the chance to experience this feelings up to full stopping to focus.
Now my 17-70 works fine. A smile for some $100

but what to do!

Not sure this will always solve it. I had mine changed maybe 2 or 3 times. Then it turned out the lens was a returned item I bought as new. So I contacted the store, and eventually got a new sample that focuses a lot better.

GlennG · 02-07-2016, 02:03 PM

Originally posted by Murra54

has anyone else had this happen? I don't really want to replace this lens as it is my walk around.

I am not sure that I've experienced this. I will try it with my 17-70. However, I'm not sure what I'm testing, exactly. My 17-70 SDM has been replaced once. As the first responder stated, it began the way you described, then continued on to "full" failure. I sent it for repair. When I received the lens back, it had the new SDM motor that was supposedly improved from the old version. I believed things were good for a while, then (some months later) I noticed that the focusing issues at the longer end (50-70 mm) had returned. I'll check focus with my polarizer, but it is a good, $100 B&W polarizer, so not one of the cheaper versions. Thanks. Glenn

jddwoods · 02-07-2016, 04:17 PM

I have same issue with mine. It can't lock focus at 70 mm with subjects that don't have a lot of contrast. I will definitely try with a circular polarizing filter. Thanks for a great idea. If it works I might start using this lens again.

Murra54 · 02-07-2016, 08:23 PM

I went out again today and the focus was all over the place. The last time I used it must have been just luck.
Definitely putting this lens in a dark cold place. Sorry to excite anyone

rawr · 02-07-2016, 09:59 PM

And I always thought the 17-70 was one of those lenses that escaped the SDM curse.

Live and learn.

GlennG · 02-08-2016, 11:02 AM

Originally posted by rawr

And I always thought the 17-70 was one of those lenses that escaped the SDM curse.

Sorry, no. Its performance seems a bit odd, however, appearing mostly at the longer end, at least at first. And, regrettably, the 17-70 cannot be hacked to make it screw drive. It is SDM or manual focus, and manual focus is difficult due to a short travel focus ring.

GlennG · 02-09-2016, 09:42 AM

Originally posted by GlennG

I will try it with my 17-70.

I just tried with the 17-70 with and without the CP - no discernable difference. Great focus at all lengths at 50 mm and less. Mostly reliable focus up to 60, but as you go from 60 to 70 mm focal length the focusing ability gets very spotty very quickly. Some shots at 70 can occur, but mostly not, and then seems to be a random shot that will focus and picture takes. Sorry.

Murra54 · 02-09-2016, 02:45 PM

I have had another try myself and I have now put the lens in the drawer for good. I must have had one good day where everything decided to work as designed.
I am unlikely to use this lens again. I am fortunate that I have also the 16 - 45 f4 which I will now have to use for the short end of the telephoto range.
(I bought the 17 - 70 because I found the zoom range ideal for a walk around lens)
I have good lenses that cover the range from 24mm up.

IchabodCrane · 02-09-2016, 04:16 PM

My DA 17-70 focuses fine at 70 mm. Pretty darn sharp with excellent contrast for a zoom, too.

GlennG · 02-10-2016, 03:42 PM

Originally posted by Murra54

I have had another try myself and I have now put the lens in the drawer for good. I must have had one good day where everything decided to work as designed. I am unlikely to use this lens again. I am fortunate that I have also the 16 - 45 f4 which I will now have to use for the short end of the telephoto range. (I bought the 17 - 70 because I found the zoom range ideal for a walk around lens)I have good lenses that cover the range from 24mm up.

I also tried my 17-70 on the K100dS (before it was on my K-5) and there was no perceptible focusing difference for me K-5 vs K100dS. The fingers on the focusing ring technique helped just a bit to get focus lock, but when I looked at some of the photos, it appeared that some of them were very much out of focus and I'm presuming that I was interfering with or changing focus somehow, yet allowing t he camera to actually take the shot. So while I got a shot, it was not a good one.

This is all very regrettable, as the lens is really very sharp with great contrast, and quite a winner from an optical only standpoint. What I have now is a great 17-50 f/4 lens that MIGHT get a longer shot once in a while. I believe I'll sell it, but it will only be right to make notice of the focus issues and the lens will have to be marked way down. But nonetheless, someone may want it. You mention your 16-45 and that lens was in strong competition with the 17-70 when I purchased it, but I selected the 17-70 based on the Photozone conclusion that this lens was the most desirable of all standard Pentax zooms. That was in late 2010 and all the information about the focus issues had not yet emerged - at all as I recall. Now, after the 17-70 cost of about $330 plus a SDM repair of $200, I feel a bit let down by the experience. I wish I had just bought the 16-45 with its oddities and just gotten on with things. We never really know the whole story until the whole story happens, do we? Oh, well.

Murra54 · 02-10-2016, 05:03 PM

I am using 16 - 45 now and finding that it functions satisfactorily as a walk around lens.
It is a pity the focus failed on the 17-70 because my copy was very sharp, focussed quickly, when it worked, and covered the zoom range I liked.
I also chose it after reading the Photozone review. I haven't pursued the cost of replacing/repairing the SDM which
I assume would amount to nearly the same as buying a replacement lens.
I am not, at this stage, prepared to accept the disappointment of a second failure, should it occur. (Good money after Bad principle.)
My new 60-250 arrived this morning so I will spend the next few days playing with it.
Cheers
Peter

**hyyz** · 02-10-2016, 07:43 PM

My 17-70 gives me the exactly same frustration as those described in this thread. From these complaints of the same focus issue, I believe it is design flaw. I no longer use my 17-70 and won't buy any SDM lens if I have alternatives.

02-07-2016, 02:21 AM	#1
Murra54 Veteran Member Join Date: Sep 2014 Location: Bendigo, Victoria Posts: 389	DA 17-70 f4 focus I have been experiencing all the difficulties that other people have reported with the focusing at the longer end of this lens. i was out using this lens, I like the range, three days ago and I have only just realised that I did not experience any of the normal hunting and stopping of previous experience. The only difference was that I was trying an inexpensive circular polariser earlier in the day and had not remove it. I just did a quick test in the back yard with polariser on and with it off and found that the lens focuses much better with the polariser on than it does with it off. Not very technical I know. has anyone else had this happen? I don't really want to replace this lens as it is my walk around.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
For Sale - Sold: LOOKING FOR OFFERS Pentax da 17-70 f4	jkglogau	Sold Items	20	11-14-2014 04:59 AM
DA 17-70/4 Focus Shift?	zosxavius	Pentax SLR Lens Discussion	4	07-31-2014 08:00 PM
For Sale - Sold: Da 17-70 f4 sdm	vrubel	Sold Items	2	02-04-2014 06:16 AM
Tamron 17-50 (€300) VS. Sigma 17-70 f4.5(€380) VS. DA 18-135 (€450)	Tomm	Pentax SLR Lens Discussion	23	03-25-2012 10:01 PM

02-07-2016, 02:50 AM	#2
HYS Veteran Member Join Date: Mar 2013 Photos: Gallery Posts: 377	Change the SDM motor. It starts in this way. I had the chance to experience this feelings up to full stopping to focus. Now my 17-70 works fine. A smile for some $100 but what to do!

02-07-2016, 05:01 AM	#3
starbase218 Inactive Account Join Date: Sep 2009 Location: Planet Earth, Sol system, Milky Way galaxy, Universe Posts: 1,119	Originally posted by HYS Change the SDM motor. It starts in this way. I had the chance to experience this feelings up to full stopping to focus. Now my 17-70 works fine. A smile for some $100 but what to do! Not sure this will always solve it. I had mine changed maybe 2 or 3 times. Then it turned out the lens was a returned item I bought as new. So I contacted the store, and eventually got a new sample that focuses a lot better.

02-07-2016, 02:03 PM	#4
GlennG Veteran Member Join Date: Aug 2010 Location: Houston, Texas Posts: 824	Originally posted by Murra54 has anyone else had this happen? I don't really want to replace this lens as it is my walk around. I am not sure that I've experienced this. I will try it with my 17-70. However, I'm not sure what I'm testing, exactly. My 17-70 SDM has been replaced once. As the first responder stated, it began the way you described, then continued on to "full" failure. I sent it for repair. When I received the lens back, it had the new SDM motor that was supposedly improved from the old version. I believed things were good for a while, then (some months later) I noticed that the focusing issues at the longer end (50-70 mm) had returned. I'll check focus with my polarizer, but it is a good, $100 B&W polarizer, so not one of the cheaper versions. Thanks. Glenn

02-07-2016, 04:17 PM	#5
jddwoods Pentaxian Join Date: Nov 2012 Location: Newark, Delaware Posts: 1,035	I have same issue with mine. It can't lock focus at 70 mm with subjects that don't have a lot of contrast. I will definitely try with a circular polarizing filter. Thanks for a great idea. If it works I might start using this lens again.

02-07-2016, 08:23 PM	#6
Murra54 Veteran Member Join Date: Sep 2014 Location: Bendigo, Victoria Posts: 389 Original Poster	I went out again today and the focus was all over the place. The last time I used it must have been just luck. Definitely putting this lens in a dark cold place. Sorry to excite anyone

02-07-2016, 09:59 PM	#7
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	And I always thought the 17-70 was one of those lenses that escaped the SDM curse. Live and learn.

02-08-2016, 11:02 AM	#8
GlennG Veteran Member Join Date: Aug 2010 Location: Houston, Texas Posts: 824	Originally posted by rawr And I always thought the 17-70 was one of those lenses that escaped the SDM curse. Sorry, no. Its performance seems a bit odd, however, appearing mostly at the longer end, at least at first. And, regrettably, the 17-70 cannot be hacked to make it screw drive. It is SDM or manual focus, and manual focus is difficult due to a short travel focus ring.

02-09-2016, 09:42 AM	#9
GlennG Veteran Member Join Date: Aug 2010 Location: Houston, Texas Posts: 824	Originally posted by GlennG I will try it with my 17-70. I just tried with the 17-70 with and without the CP - no discernable difference. Great focus at all lengths at 50 mm and less. Mostly reliable focus up to 60, but as you go from 60 to 70 mm focal length the focusing ability gets very spotty very quickly. Some shots at 70 can occur, but mostly not, and then seems to be a random shot that will focus and picture takes. Sorry.

02-09-2016, 02:45 PM	#10
Murra54 Veteran Member Join Date: Sep 2014 Location: Bendigo, Victoria Posts: 389 Original Poster	I have had another try myself and I have now put the lens in the drawer for good. I must have had one good day where everything decided to work as designed. I am unlikely to use this lens again. I am fortunate that I have also the 16 - 45 f4 which I will now have to use for the short end of the telephoto range. (I bought the 17 - 70 because I found the zoom range ideal for a walk around lens) I have good lenses that cover the range from 24mm up.

02-09-2016, 04:16 PM	#11
IchabodCrane Veteran Member Join Date: Sep 2012 Photos: Gallery \| Albums Posts: 1,728	My DA 17-70 focuses fine at 70 mm. Pretty darn sharp with excellent contrast for a zoom, too.

Thread Tools	Search this Thread
	Search this Thread: Advanced Search

02-10-2016, 03:42 PM	#12
GlennG Veteran Member Join Date: Aug 2010 Location: Houston, Texas Posts: 824	Originally posted by Murra54 I have had another try myself and I have now put the lens in the drawer for good. I must have had one good day where everything decided to work as designed. I am unlikely to use this lens again. I am fortunate that I have also the 16 - 45 f4 which I will now have to use for the short end of the telephoto range. (I bought the 17 - 70 because I found the zoom range ideal for a walk around lens)I have good lenses that cover the range from 24mm up. I also tried my 17-70 on the K100dS (before it was on my K-5) and there was no perceptible focusing difference for me K-5 vs K100dS. The fingers on the focusing ring technique helped just a bit to get focus lock, but when I looked at some of the photos, it appeared that some of them were very much out of focus and I'm presuming that I was interfering with or changing focus somehow, yet allowing t he camera to actually take the shot. So while I got a shot, it was not a good one. This is all very regrettable, as the lens is really very sharp with great contrast, and quite a winner from an optical only standpoint. What I have now is a great 17-50 f/4 lens that MIGHT get a longer shot once in a while. I believe I'll sell it, but it will only be right to make notice of the focus issues and the lens will have to be marked way down. But nonetheless, someone may want it. You mention your 16-45 and that lens was in strong competition with the 17-70 when I purchased it, but I selected the 17-70 based on the Photozone conclusion that this lens was the most desirable of all standard Pentax zooms. That was in late 2010 and all the information about the focus issues had not yet emerged - at all as I recall. Now, after the 17-70 cost of about $330 plus a SDM repair of $200, I feel a bit let down by the experience. I wish I had just bought the 16-45 with its oddities and just gotten on with things. We never really know the whole story until the whole story happens, do we? Oh, well.

02-10-2016, 05:03 PM	#13
Murra54 Veteran Member Join Date: Sep 2014 Location: Bendigo, Victoria Posts: 389 Original Poster	I am using 16 - 45 now and finding that it functions satisfactorily as a walk around lens. It is a pity the focus failed on the 17-70 because my copy was very sharp, focussed quickly, when it worked, and covered the zoom range I liked. I also chose it after reading the Photozone review. I haven't pursued the cost of replacing/repairing the SDM which I assume would amount to nearly the same as buying a replacement lens. I am not, at this stage, prepared to accept the disappointment of a second failure, should it occur. (Good money after Bad principle.) My new 60-250 arrived this morning so I will spend the next few days playing with it. Cheers Peter

02-10-2016, 07:43 PM	#14
hyyz Site Supporter Join Date: Jan 2008 Location: Michigan Posts: 478	My 17-70 gives me the exactly same frustration as those described in this thread. From these complaints of the same focus issue, I believe it is design flaw. I no longer use my 17-70 and won't buy any SDM lens if I have alternatives.