Auto Focus issues

Mark K5 · 08-20-2014, 09:30 AM

My K3 had real trouble focusing on my recent trip to New Orleans.

I was wondering if I should be cleaning the contacts with isopropyl alcohol on both the lens and camera body.

**jatrax** · 08-20-2014, 10:19 AM

Originally posted by Mark K5

I was wondering if I should be cleaning the contacts with isopropyl alcohol on both the lens and camera body.

No. Not unless you are really seeing communication issues. You might try buffing the contacts, lightly, with a microfiber cloth but I would not think alcohol would be needed.

**MJSfoto1956** · 08-20-2014, 10:42 AM

when I first got the K-3 (my first Pentax btw) I too had "random" focus problems. So I attempted to do a focus correction but -10 was not "enough" for this particular lens. So I then added -10 "globally" (i.e. for all lenses) and this lens -- as well as all my other Pentax lenses -- now focuses like a champ. In my case, I believe my camera body optics need -20 for all my lenses which makes me think I simply need a repair but I have not done so as the images are spot on now. My theory is that when your AF is off as much as mine was that the algorithms used to calculate where to focus simply break down and provide unexpected results. In my case, I was getting both front and rear focusing from the same lens. For me this is a big clue as to what might be going on "behind the scenes". Anyway, my advice is to get your lens focus correction set properly and don't be afraid to set both INDIVIDUAL and GLOBAL settings if necessary -- AFAIK they appear to be cumulative: e.g. -10 individual and -10 global = -20 in total.

YMMV

Michael

stevebrot · 08-20-2014, 11:08 AM

Originally posted by Mark K5

My K3 had real trouble focusing on my recent trip to New Orleans.

I was wondering if I should be cleaning the contacts with isopropyl alcohol on both the lens and camera body.

Was your problem a failure to acquire focus or a failure of the camera to recognize that an AF lens was mounted or failure to acquire accurate focus?

What is it that would lead you to believe that there is a problem with the contacts? There is only one contact that is used for AF control and only then with motor-in-lens designs. Poor connectivity through the data contact would lead to constant or intermittent full AF failure or (my understanding) inordinate "hunting" with failure to acquire focus. I have been shooting Pentax AF since 2007 and have never had an AF issue related to the contacts.

A failure to acquire focus is most likely an issue with the light or subject. A failure to accurately acquire focus may be cause for calibration or an indication of improper usage.

As with the jatrax's comment above, I would avoid alcohol in favor of a microfiber cloth.

Steve

Last edited by stevebrot; 08-20-2014 at 11:13 AM.

Mark K5 · 08-21-2014, 09:12 AM

I had my DA* 16-50 on the camera and for the first time it would not focus. When I switch to my DA* 60-250 everything worked fine. Then I put the 16-50 on again and it was working fine again.
It was mid day and the sun was shining. It was not a low light situation.
Both lens worked fine after the lens switches and had worked well before this situation.
That's what lead me to think it was a contact thing.

stevebrot · 08-21-2014, 12:36 PM

Originally posted by Mark K5

I had my DA* 16-50 on the camera and for the first time it would not focus.

Could not acquire focus or did not even try?

Steve

**jatrax** · 08-21-2014, 11:19 PM

Originally posted by Mark K5

I had my DA* 16-50 on the camera and for the first time it would not focus.

Possible beginning of SDM failure on the 16-50? Mine was intermittent for quite some time before it became bothersome enough to send in for repair. It would be fine for days then "act up" then be fine again, but gradually the amount of "not fine" time exceeded the amount of "fine" time.

stevebrot · 08-22-2014, 04:34 PM

Originally posted by jatrax

Possible beginning of SDM failure on the 16-50? Mine was intermittent for quite some time before it became bothersome enough to send in for repair. It would be fine for days then "act up" then be fine again, but gradually the amount of "not fine" time exceeded the amount of "fine" time.

That is my fear as well, but did not want to say anything without a more definitive description of the problem.

Steve

awaldram · 08-23-2014, 02:02 AM

Originally posted by stevebrot

That is my fear as well, but did not want to say anything without a more definitive description of the problem.

Steve

I would have thought a single instance of mount camera no AF would indicate a miss seated mount. and subsequent failure woudl indicate dirty contacts.
Only when the obvious has been discounted would the SDM 'issue' be worth considering.

Maybe to much 'the sky is falling' and a more realistic interpretation is required in this forum!!

stevebrot · 08-23-2014, 09:33 AM

Originally posted by awaldram

I would have thought a single instance of mount camera no AF would indicate a miss seated mount. and subsequent failure woudl indicate dirty contacts.
Only when the obvious has been discounted would the SDM 'issue' be worth considering.

Maybe to much 'the sky is falling' and a more realistic interpretation is required in this forum!!

That is why I kept asking for what the OP means by "trouble focusing" or "would not focus". It could indeed be an issue with the contacts or something as simple as not mounting cleanly, but without a good description of the problem there is no sense offering advice.

About the only thing that is known at this point is that another SDM lens works fine thereby ruling out the body as the fault source. Other possible causes include:

Bad power coupling on lens (oxidation, gunge)
Bad data pin connectivity on lens (oxidation, gunge)
Bad motor on lens
Bad controller or power circuitry on lens
Bad optics (if not able to manually focus)
User error (inadequate light and/or subject contrast to allow for auto focus)

Cleaning the power and data contacts won't hurt though doing so (particularly with solvent) should not be considered as some kind of required regular maintenance. Probably the easiest way to determine if there is a data contact issue is to simply take a photo when there is a failed AF attempt and review the image with detail information displayed. If the lens is not identified, the data connection or supporting circuitry is not working. If the data connection is bad, the AF system will fail.

After having cleaned those pesky contacts:

Manual focus work?
Lens detected (see paragraph above)
Motor engaging?
AF system able to consistently acquire focus with a high contrast target at moderate distance in good light?

A no answer to any of the above four points indicate a fault with the lens systems.

Steve

Mark K5 · 08-27-2014, 04:02 PM

Sadly it appears that the motors are gone. Tried the 16-50 on my old K5 and the same problem.

Cleaning the contacts appeared to do nothing even though they were pretty dirty.

Let's see how that credit card warranty extension works.

Bit of drag but I still love the lens and it has quite a few miles on it now.

Mark K5 · 08-27-2014, 05:09 PM

Great news! Pentax Canada - Two Year Warranty - American Express Gold Card - Plus one year warranty.

DA* 16-50 still under warranty.

YES!!!

Good to keep all paper work and statements.

---------- Post added 08-27-14 at 05:11 PM ----------

Thanks for all the great tips and replies.

**jatrax** · 08-27-2014, 07:51 PM

Originally posted by Mark K5

Good to keep all paper work and statements.

+1000 on that! Glad you are in warranty.

Unregistered User · 08-28-2014, 12:45 AM

Sometimes it can be worth contacting the workshop even if the warranty has passed. My Tamron 17-50 needed adjustment and the warranty ended 6 weeks before I got to it. Pentax Sweden did it anyway without charge.

danny09 · 09-20-2014, 06:28 PM

Spending a fortune on the SDM lenses only to have them fail is not good. Ricoh should provide lifetime warranty free of cost for all SDM lenses. The recent motors in latest pentax lenses have been very good. The 18-135 or da 20-40 mm. Can Ricoh recall all SDM lenses and retrofit it with DC motors? Wishful thinking probably.

08-20-2014, 09:30 AM	#1
Mark K5 Forum Member Join Date: Feb 2012 Location: Vancouver, BC Photos: Albums Posts: 59	Auto Focus issues My K3 had real trouble focusing on my recent trip to New Orleans. I was wondering if I should be cleaning the contacts with isopropyl alcohol on both the lens and camera body.

08-21-2014, 09:12 AM	#5
Mark K5 Forum Member Join Date: Feb 2012 Location: Vancouver, BC Photos: Albums Posts: 59 Original Poster	I had my DA* 16-50 on the camera and for the first time it would not focus. When I switch to my DA* 60-250 everything worked fine. Then I put the 16-50 on again and it was working fine again. It was mid day and the sun was shining. It was not a low light situation. Both lens worked fine after the lens switches and had worked well before this situation. That's what lead me to think it was a contact thing. Last edited by Mark K5; 08-21-2014 at 09:13 AM. Reason: typing error

08-23-2014, 09:33 AM	#10
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by awaldram I would have thought a single instance of mount camera no AF would indicate a miss seated mount. and subsequent failure woudl indicate dirty contacts. Only when the obvious has been discounted would the SDM 'issue' be worth considering. Maybe to much 'the sky is falling' and a more realistic interpretation is required in this forum!! That is why I kept asking for what the OP means by "trouble focusing" or "would not focus". It could indeed be an issue with the contacts or something as simple as not mounting cleanly, but without a good description of the problem there is no sense offering advice. About the only thing that is known at this point is that another SDM lens works fine thereby ruling out the body as the fault source. Other possible causes include: Bad power coupling on lens (oxidation, gunge) Bad data pin connectivity on lens (oxidation, gunge) Bad motor on lens Bad controller or power circuitry on lens Bad optics (if not able to manually focus) User error (inadequate light and/or subject contrast to allow for auto focus) Cleaning the power and data contacts won't hurt though doing so (particularly with solvent) should not be considered as some kind of required regular maintenance. Probably the easiest way to determine if there is a data contact issue is to simply take a photo when there is a failed AF attempt and review the image with detail information displayed. If the lens is not identified, the data connection or supporting circuitry is not working. If the data connection is bad, the AF system will fail. After having cleaned those pesky contacts: Manual focus work? Lens detected (see paragraph above) Motor engaging? AF system able to consistently acquire focus with a high contrast target at moderate distance in good light? A no answer to any of the above four points indicate a fault with the lens systems. Steve

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08-20-2014, 10:19 AM	#2
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by Mark K5 I was wondering if I should be cleaning the contacts with isopropyl alcohol on both the lens and camera body. No. Not unless you are really seeing communication issues. You might try buffing the contacts, lightly, with a microfiber cloth but I would not think alcohol would be needed.

08-20-2014, 10:42 AM	#3
MJSfoto1956 Site Supporter Join Date: Dec 2013 Location: Boston Posts: 1,305	when I first got the K-3 (my first Pentax btw) I too had "random" focus problems. So I attempted to do a focus correction but -10 was not "enough" for this particular lens. So I then added -10 "globally" (i.e. for all lenses) and this lens -- as well as all my other Pentax lenses -- now focuses like a champ. In my case, I believe my camera body optics need -20 for all my lenses which makes me think I simply need a repair but I have not done so as the images are spot on now. My theory is that when your AF is off as much as mine was that the algorithms used to calculate where to focus simply break down and provide unexpected results. In my case, I was getting both front and rear focusing from the same lens. For me this is a big clue as to what might be going on "behind the scenes". Anyway, my advice is to get your lens focus correction set properly and don't be afraid to set both INDIVIDUAL and GLOBAL settings if necessary -- AFAIK they appear to be cumulative: e.g. -10 individual and -10 global = -20 in total. YMMV Michael

08-20-2014, 11:08 AM	#4
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Mark K5 My K3 had real trouble focusing on my recent trip to New Orleans. I was wondering if I should be cleaning the contacts with isopropyl alcohol on both the lens and camera body. Was your problem a failure to acquire focus or a failure of the camera to recognize that an AF lens was mounted or failure to acquire accurate focus? What is it that would lead you to believe that there is a problem with the contacts? There is only one contact that is used for AF control and only then with motor-in-lens designs. Poor connectivity through the data contact would lead to constant or intermittent full AF failure or (my understanding) inordinate "hunting" with failure to acquire focus. I have been shooting Pentax AF since 2007 and have never had an AF issue related to the contacts. A failure to acquire focus is most likely an issue with the light or subject. A failure to accurately acquire focus may be cause for calibration or an indication of improper usage. As with the jatrax's comment above, I would avoid alcohol in favor of a microfiber cloth. Steve Last edited by stevebrot; 08-20-2014 at 11:13 AM.

08-21-2014, 12:36 PM	#6
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Mark K5 I had my DA* 16-50 on the camera and for the first time it would not focus. Could not acquire focus or did not even try? Steve

08-21-2014, 11:19 PM	#7
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by Mark K5 I had my DA* 16-50 on the camera and for the first time it would not focus. Possible beginning of SDM failure on the 16-50? Mine was intermittent for quite some time before it became bothersome enough to send in for repair. It would be fine for days then "act up" then be fine again, but gradually the amount of "not fine" time exceeded the amount of "fine" time.

08-22-2014, 04:34 PM	#8
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by jatrax Possible beginning of SDM failure on the 16-50? Mine was intermittent for quite some time before it became bothersome enough to send in for repair. It would be fine for days then "act up" then be fine again, but gradually the amount of "not fine" time exceeded the amount of "fine" time. That is my fear as well, but did not want to say anything without a more definitive description of the problem. Steve

08-23-2014, 02:02 AM	#9
awaldram Veteran Member Join Date: May 2008 Location: Hampshire Photos: Gallery Posts: 732	Originally posted by stevebrot That is my fear as well, but did not want to say anything without a more definitive description of the problem. Steve I would have thought a single instance of mount camera no AF would indicate a miss seated mount. and subsequent failure woudl indicate dirty contacts. Only when the obvious has been discounted would the SDM 'issue' be worth considering. Maybe to much 'the sky is falling' and a more realistic interpretation is required in this forum!!

08-27-2014, 04:02 PM	#11
Mark K5 Forum Member Join Date: Feb 2012 Location: Vancouver, BC Photos: Albums Posts: 59 Original Poster	Sadly it appears that the motors are gone. Tried the 16-50 on my old K5 and the same problem. Cleaning the contacts appeared to do nothing even though they were pretty dirty. Let's see how that credit card warranty extension works. Bit of drag but I still love the lens and it has quite a few miles on it now.

08-27-2014, 05:09 PM	#12
Mark K5 Forum Member Join Date: Feb 2012 Location: Vancouver, BC Photos: Albums Posts: 59 Original Poster	Great news! Pentax Canada - Two Year Warranty - American Express Gold Card - Plus one year warranty. DA* 16-50 still under warranty. YES!!! Good to keep all paper work and statements. ---------- Post added 08-27-14 at 05:11 PM ---------- Thanks for all the great tips and replies.

08-27-2014, 07:51 PM	#13
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by Mark K5 Good to keep all paper work and statements. +1000 on that! Glad you are in warranty.

08-28-2014, 12:45 AM	#14
Unregistered User Guest	Sometimes it can be worth contacting the workshop even if the warranty has passed. My Tamron 17-50 needed adjustment and the warranty ended 6 weeks before I got to it. Pentax Sweden did it anyway without charge.

09-20-2014, 06:28 PM	#15
danny09 Veteran Member Join Date: May 2008 Location: SF Bay Area Posts: 417	Spending a fortune on the SDM lenses only to have them fail is not good. Ricoh should provide lifetime warranty free of cost for all SDM lenses. The recent motors in latest pentax lenses have been very good. The 18-135 or da 20-40 mm. Can Ricoh recall all SDM lenses and retrofit it with DC motors? Wishful thinking probably.