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11-27-2022, 10:31 PM   #1
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Pentax 17-70 f4 question

Apologies if this has been asked before, but I have searched and found nothing.

I have had a Pentax 17-70 f4 since new, and it has been a fantastic lens, significantly sharper than the 16-50 f2.8, which I also have.... but the 17-70 started having AF issues a few years back which is no doubt the SDM dying, and is now unreliable, leaving me with the 16-50 as my main lens in that focal length area on a K3.
As I am now doing an increasing amount of photography for a local newspaper the 17-70 range is better than 16-50 and I am missing it.

I can buy a brand new 17-70 but I am wondering if anyone has any information on the SDM ? I have heard / read somewhere that the SDM issue " has been solved" on later models of the 17-70 f4, but how do you know which is a "later model/version" , as far as I am aware there was no official release of an updated version. If the serial numbers are an indicator, does anyone know from where the (lets call it "updated") model/version starts ?

Yes, I know I can buy a 18-135, or 16-85 or 28-105 to replace it but already have the 24-70 on the K1ii, great lens, which is a bit short, and I mainly use a Sig 70-200 f2.8 on that body. Other bodies are K3 (i, ii & iii).
I also have a Tamron 28-300 which I used on the weekend but was disappointed with the results, also have a Sigma 18-250 but that wont be any better.
The sort of shooting situations I find myself in vary a lot, indoors, outdoors, good light, poor light, and flash is not always an option, sometimes ISO 400 or 800 is better and thats where the lens' ability in low light starts to come into play.


So I have a dilemna. I know the 17-70 can give me the results I need & want, but not interested if the SDM thing is unsolved. The 16-50 is a second best option based on image quality and range. I do not know the 18-135, 16-85 or 28-105 at all and reviews / reports are so varied I am not convinced on any of them.

Look forward to your replies.
Cheers

11-28-2022, 12:58 AM - 1 Like   #2
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As far as I know all SDM lenses could be converted to screwdrive focusing. More info here: How To: Convert SDM to ScrewDrive + Video - PentaxForums.com
This looks as good solution, no need to spend more money... No need to sell or repair the lens. Good luck to you.
11-28-2022, 02:28 AM   #3
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UncleVanya provides a conversion service, but I don't know that I've seen the 17-70mm mentioned elsewhere as being able to be converted.

Here's what UncleVanya advises. Note that there seems to be agreement that the 60-250mm cannot be converted.
You might contact him and see what he thinks about the 17-70mm.

QuoteQuote:
I have successfully converted all of these lenses:
DA* 16-50
DA* 50-135
DA* 200
DA* 300

I am unable to convert the DA* 60-250.

Last edited by yucatanPentax; 11-28-2022 at 02:34 AM.
11-28-2022, 02:36 AM - 1 Like   #4
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Not all SDM lenses have the screwdrive focus option. The DA* 55 and the 17-70 are both internal motor focus only.

11-28-2022, 03:26 AM - 1 Like   #5
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QuoteOriginally posted by Mallee Boy Quote
Apologies if this has been asked before, but I have searched and found nothing.

I have had a Pentax 17-70 f4 since new, and it has been a fantastic lens, significantly sharper than the 16-50 f2.8, which I also have.... but the 17-70 started having AF issues a few years back which is no doubt the SDM dying, and is now unreliable, leaving me with the 16-50 as my main lens in that focal length area on a K3.
As I am now doing an increasing amount of photography for a local newspaper the 17-70 range is better than 16-50 and I am missing it.

I can buy a brand new 17-70 but I am wondering if anyone has any information on the SDM ? I have heard / read somewhere that the SDM issue " has been solved" on later models of the 17-70 f4, but how do you know which is a "later model/version" , as far as I am aware there was no official release of an updated version. If the serial numbers are an indicator, does anyone know from where the (lets call it "updated") model/version starts ?

Yes, I know I can buy a 18-135, or 16-85 or 28-105 to replace it but already have the 24-70 on the K1ii, great lens, which is a bit short, and I mainly use a Sig 70-200 f2.8 on that body. Other bodies are K3 (i, ii & iii).
I also have a Tamron 28-300 which I used on the weekend but was disappointed with the results, also have a Sigma 18-250 but that wont be any better.
The sort of shooting situations I find myself in vary a lot, indoors, outdoors, good light, poor light, and flash is not always an option, sometimes ISO 400 or 800 is better and thats where the lens' ability in low light starts to come into play.


So I have a dilemna. I know the 17-70 can give me the results I need & want, but not interested if the SDM thing is unsolved. The 16-50 is a second best option based on image quality and range. I do not know the 18-135, 16-85 or 28-105 at all and reviews / reports are so varied I am not convinced on any of them.

Look forward to your replies.
Cheers
I also have a focussing problem with the 17-70 F4.
In my case: I switch the camera to live view. Then I subsequently turn the fucus ring, try to auto-focus a subject, turn the ring, try auto-fucussing, ...
After a view cycles the lens focusses accurately and quickly.
I then turn the camera back to optical viewfinder and the autofocus works perfectly. I do not turn the camera off.
But even when I do turn the camera off, if it does not take to long between switching the camera on again, the auto-focus still works.
I hope this helps for you too.
11-28-2022, 05:26 AM   #6
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The 16-85 has a DC motor in lieu of SDM and is rated better by our users that the 17-70:
16-85 user ratings
17-70 user ratings

But since you already have the D FA 24-70 sitting idle you could use that on the K-3. Unless, of course, you need the wider angle of view that the range 16/17mm to 24mm gives you.
11-28-2022, 05:46 AM - 1 Like   #7
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The 17-70 cannot be converted to screw drive. It is SDM only. The lens is discontinued and can only be bought used as far as I know. I faced the same dilemma as you about 3 years ago, the SDM on mine failed completely. This is a well documented issue with this lens. Like you, I really liked the image quality of this lens when it worked. Unfortunately I found it unusable as a manual focus lens due to the very loose and short throw of the focus ring. That left me at the time, and you now with 3 options.
1. Have the lens repaired
2. Buy a used one, they periodically come up for sale at prices lower than quoted repair cost.
3. Replace it with something else. In my case I found a used 16-85 at a reasonable cost in like new condition. Personally I find the 16-85 better in every way except it doesn't have the constant f 4 aperture. It is sharper, has better build quality and has a reliable autofocus motor.
If I were in your position, since you already have 2 good alternative lenses I would probably be satisfied with what you already have. If you want or need to replace it, I would recommend either the 18-135 or the 16-85 after considering which better fits your needs.

11-28-2022, 07:50 AM   #8
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The 17-70 is a great lens but sdm failures happen. I had a good one that was a refurb that n never died on my dad or me that was given to my niece, but she eventually switched brands so I donít know the long term fate of that lens. The Sigma 17-70 f2.8-4 might work well for you. There are two version and I donít recall what the differences are.
11-28-2022, 10:02 AM - 2 Likes   #9
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About eight, nine years ago I ended up purchasing two copies of the DA 17-70, neither of which would focus accurately. The first copy was not capable of informing the camera of the correct focal length (it claimed all focal lengths were 43mm) and the second was just not capable of focusing accurately (nor was it correctible though in-camera adjustments). It had nothing to do with the SDM motor, which worked in both cases. So the lens is capable of having more AF issues other than just the SDM going belly up. I ended having to use my second copy of the optic solely in manual focus, which I did for several years. When the DA 16-85, I purchased a copy of that lens and got rid of the DA 17-70 for good. Nice lens optically, but seemingly very prone to AF issues. I've had no such issues at all with DA 16-85 (which is optically superior as well).
11-28-2022, 02:58 PM   #10
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QuoteOriginally posted by PardonMyShutterSound Quote
As far as I know all SDM lenses could be converted to screwdrive focusing. More info here: How To: Convert SDM to ScrewDrive + Video - PentaxForums.com
This looks as good solution, no need to spend more money... No need to sell or repair the lens. Good luck to you.
Thanks for your response, ay be issues with this.

---------- Post added 11-29-22 at 08:58 AM ----------

QuoteOriginally posted by yucatanPentax Quote
UncleVanya provides a conversion service, but I don't know that I've seen the 17-70mm mentioned elsewhere as being able to be converted.

Here's what UncleVanya advises. Note that there seems to be agreement that the 60-250mm cannot be converted.
You might contact him and see what he thinks about the 17-70mm.
Thankyou

---------- Post added 11-29-22 at 08:59 AM ----------

QuoteOriginally posted by pjv Quote
Not all SDM lenses have the screwdrive focus option. The DA* 55 and the 17-70 are both internal motor focus only.
Thankyou.

---------- Post added 11-29-22 at 09:02 AM ----------

QuoteOriginally posted by PJvE Quote
I also have a focussing problem with the 17-70 F4.
In my case: I switch the camera to live view. Then I subsequently turn the fucus ring, try to auto-focus a subject, turn the ring, try auto-fucussing, ...
After a view cycles the lens focusses accurately and quickly.
I then turn the camera back to optical viewfinder and the autofocus works perfectly. I do not turn the camera off.
But even when I do turn the camera off, if it does not take to long between switching the camera on again, the auto-focus still works.
I hope this helps for you too.
Thankyou. Yes, I do something similar when using it for landscape work (with mixed results) but when using it for photojournalism I need everything to work first time every time and quickly as opportunities are often fleeting.

---------- Post added 11-29-22 at 09:05 AM ----------

QuoteOriginally posted by Ole Quote
The 16-85 has a DC motor in lieu of SDM and is rated better by our users that the 17-70:
16-85 user ratings
17-70 user ratings

But since you already have the D FA 24-70 sitting idle you could use that on the K-3. Unless, of course, you need the wider angle of view that the range 16/17mm to 24mm gives you.
Thanks Ole, I do use the 24-70 quite a bit on both K3 & K1 and its too long on the wide end on APSC, sounds like the 16-85 is the way to go.
Thankyou.
11-28-2022, 03:07 PM   #11
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QuoteOriginally posted by Mallee Boy Quote
I do not know the 18-135, 16-85 or 28-105 at all and reviews / reports are so varied I am not convinced on any of them.
I don't have the 16-50, 17-70 or 28-85, but do I have the 18-135, 16-85, 20-40 Ltd, as well as a number of primes in that range (DA 35 f2.4, FA 43 Ltd, FA 50 Macro, FA 77 Ltd, DFA 100 macro WR).

As a potential replacement for the 17-70, the clear choice would be the 16-85. It's a really really good lens, especially for outdoor use. Excellent centre sharpness and very good across the frame stopped down. WR and HD. I know some people insist on constant aperture, and you might want f4 at the long end, but you have the 70-200 if you need a wider aperture at the mid-tele lengths. The only real knock on the 16-85 is that some people find the image won't show when the lens is being zoomed in and out. (Mine doesn't do that.)

If you are shooting indoors at lot, without flash, your choice is either to push the ISO (should be plenty of scope with the K-3iii) or use a f2.8 zoom. In the latter case, if the 24-70 isn't wide enough, maybe you should look at the new PLM version of the DA*16-50 f2.8. Seems a cracker of a lens.

Move quickly to get the November sale price. DCXpert prices are very good right now with the Black Friday discounts (dcxpert | eBay Stores) - better than Pentax Aust - but it ends tomorrow night (Wed 30 Nov).
11-28-2022, 03:09 PM   #12
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QuoteOriginally posted by jddwoods Quote
The 17-70 cannot be converted to screw drive. It is SDM only. The lens is discontinued and can only be bought used as far as I know. I faced the same dilemma as you about 3 years ago, the SDM on mine failed completely. This is a well documented issue with this lens. Like you, I really liked the image quality of this lens when it worked. Unfortunately I found it unusable as a manual focus lens due to the very loose and short throw of the focus ring. That left me at the time, and you now with 3 options.
1. Have the lens repaired
2. Buy a used one, they periodically come up for sale at prices lower than quoted repair cost.
3. Replace it with something else. In my case I found a used 16-85 at a reasonable cost in like new condition. Personally I find the 16-85 better in every way except it doesn't have the constant f 4 aperture. It is sharper, has better build quality and has a reliable autofocus motor.
If I were in your position, since you already have 2 good alternative lenses I would probably be satisfied with what you already have. If you want or need to replace it, I would recommend either the 18-135 or the 16-85 after considering which better fits your needs.
Thanks JD. Not sure I would say the 16-50 is a good alternative, actually fairly disappointed with the (soft) results from that lens. Someone is advertising new 17-70's, but I'm hesitant, probably better to spend the extra few hundred and get the 16-85. Thanks for your input.

---------- Post added 11-29-22 at 09:10 AM ----------

QuoteOriginally posted by UncleVanya Quote
The 17-70 is a great lens but sdm failures happen. I had a good one that was a refurb that n never died on my dad or me that was given to my niece, but she eventually switched brands so I donít know the long term fate of that lens. The Sigma 17-70 f2.8-4 might work well for you. There are two version and I donít recall what the differences are.
Heya Uncle. Trust your keeping well. Thanks for the input.

---------- Post added 11-29-22 at 09:12 AM ----------

QuoteOriginally posted by northcoastgreg Quote
About eight, nine years ago I ended up purchasing two copies of the DA 17-70, neither of which would focus accurately. The first copy was not capable of informing the camera of the correct focal length (it claimed all focal lengths were 43mm) and the second was just not capable of focusing accurately (nor was it correctible though in-camera adjustments). It had nothing to do with the SDM motor, which worked in both cases. So the lens is capable of having more AF issues other than just the SDM going belly up. I ended having to use my second copy of the optic solely in manual focus, which I did for several years. When the DA 16-85, I purchased a copy of that lens and got rid of the DA 17-70 for good. Nice lens optically, but seemingly very prone to AF issues. I've had no such issues at all with DA 16-85 (which is optically superior as well).
Thanks NorthCoast, note your comment re:16-85.
Cheers

---------- Post added 11-29-22 at 09:13 AM ----------

QuoteOriginally posted by Des Quote
I don't have the 16-50, 17-70 or 28-85, but do I have the 18-135, 16-85, 20-40 Ltd, as well as a number of primes in that range (DA 35 f2.4, FA 43 Ltd, FA 50 Macro, FA 77 Ltd, DFA 100 macro WR).

As a potential replacement for the 17-70, the clear choice would be the 16-85. It's a really really good lens, especially for outdoor use. Excellent centre sharpness and very good across the frame stopped down. WR and HD. I know some people insist on constant aperture, and you might want f4 at the long end, but you have the 70-200 if you need a wider aperture at the mid-tele lengths. The only real knock on the 16-85 is that some people find the image won't show when the lens is being zoomed in and out. (Mine doesn't do that.)

If you are shooting indoors at lot, without flash, your choice is either to push the ISO (should be plenty of scope with the K-3iii) or use a f2.8 zoom. In the latter case, if the 24-70 isn't wide enough, maybe you should look at the new PLM version of the DA*16-50 f2.8. Seems a cracker of a lens.

Move quickly to get the November sale price. DCXpert prices are very good right now with the Black Friday discounts (dcxpert | eBay Stores) - better than Pentax Aust - but it ends tomorrow night (Wed 30 Nov).
Thanks Des.
11-28-2022, 04:41 PM   #13
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My SMC DA* 16-50 2.8 is very sharp. When I had theK-3 it outresolved that sensor for most of the frame. Maybe the OP's copy needsfocus adjustment? I'm in Brazil working from home and visiting with my family, and the 16-50 2.8 and the 70 2.4 Limited are getting all the pictures so far...
11-28-2022, 06:41 PM   #14
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QuoteOriginally posted by Mallee Boy Quote
Thanks JD. Not sure I would say the 16-50 is a good alternative, actually fairly disappointed with the (soft) results from that lens. Someone is advertising new 17-70's, but I'm hesitant, probably better to spend the extra few hundred and get the 16-85. Thanks for your input.
I would be very hesitant to go for the supposedly new 17-70. Best to go straight to the 16-85 as others have also suggested. You will find this is a much better lens than the 17-70. I do not know what the pricing for a new 16-85 is in Australia but at the 3 major retailers in the US it is on sale so you may also be seeing discounts in Australia retailers. So, this may be a good time to treat yourself to it. Mine is by far my most used lens.

Last edited by jddwoods; 11-29-2022 at 06:24 AM.
12-22-2022, 09:34 PM   #15
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After a lot of homework and going back over my existing lens "collection" (I have accumulated way too many over the journey) and testing, I opted for a Sigma 17-50 f2.8 EX DC , new, for less than half the price of most of the Pentax offerrings amd in the case of the 16-50 plm, about a quarter of the price...sorry Pentax, I do love you, but money dont grow on trees around here.

Here is what I revisited in my collection, and I post this in the hope it may help someone else:
All used on the K3iii.

Sigma 18-250. Made myself shoot with it on an assignment which fortuneately was a bright day, so got on pretty well with it until the light began to fade and then it became a challenge to get the results I wanted. But in the right (bright, well lit) conditions a very handy option to have in the bag, particularly with its reach, but not the sharpest tool in the bag when you use the full zoom capability, the poorer the light, the poorer the result. ISO adjustments help a bit. It will stay in the kit.

Tamron 28-300: Very much the same story as the Sigma 18-250, but falls away more at 250 - 300mm and doesnt do anything special to kick the Sigma 18-250 out of the bag. Open to offers on the 28-300.

Pentax DA*16-50 F2.8:
I used it again last weekend on an evening shoot where I knew the light would be fading and I confirmed my mis-givings with this lens from the get go, at the wide end it is murky and mush, but I concluded it is also front focussing. However at the edges it is truly horrible. I shoot a few panos with this lens and when I go back and look at these again I can see my problem. Fortuneatley I packed the DA* 50-135 so was able to complete my job with that. I am going to send this back to Pentax and see what they can do with it because get away from 16mm and f2.8 to mid focal range and f5.6 + and it gets a lot better, but the edges are still weak, not rteally good enough for a "premier" quality lens. It has travelled a fair bit so maybe something has happened on a journey. I will let you know in due course.

So that was leaving me with a need in the short term and I really could not get excited about the Pentax offerings, the 18-135 only ranks slightly better from user reviews than the Sig 18-250. Some 16-85 owners are less than enthusiastic about it and all the time I am looking at the f3.5 figure and having trouble reconciling that with my useage pattern, where I can be shooting across all qualities of light.

The Sigma 17-50 f2.8 EX DC fld has pretty good reviews generally, I understand that there will always be unhappy owners for one reason or another, but it stacks up pretty well. Price wise it was a no brainer at under $500 aussie and the first shots are very pleasing. It is genuinely sharp, and yes, the edges fall away a little but are still very useable, far more so than the DA*16-50 and out of the box it needed no AF fine tuning. It is very well made and I am a happy chappy.

Merry Christmas all.
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