Strange Focus Problem with the 60-250mm

**EricBT** · 02-13-2023, 08:36 PM

Here's a focusing problem I found using the K3-III and the60-250mm. Trying out the lens today, after not using it for a while, it would not autofocus. The lens would make a slight squealing sound when trying to autofocus and the distance scale would only move slightly between the 2m and1.1m mark. The same behaviour occurred when I tried to use quick shift or by putting the lens focus switch to MF.

Oddly enough, when I set the camera body focus switch to MF it would allow full manual focus. When I removed the lens from the camera I could also now get full distance scale movement using the focusing ring.

I cleaned the contacts on both lens and body with no effect. There is no damage on the lens contacts and all seems physically OK. The K3-III has the latest firmware and I have not had any issues in the past with this lens.

My first thought was SDM failure but the fact that it tried to autofocus, and that it would only manual focus using the camera body switch or when it is disconnected, was really odd.

So I got out my old K3 and tried that. Autofocus was back working again. When I put the lens back on the K3-III full autofocus and manual focus were also working again.

I don't know what caused the issue, I had a fully charged battery in the camera, but at least it's working now. Has anyone else had similar strange issues with this or other lenses?

Last edited by EricBT; 02-13-2023 at 08:38 PM. Reason: Formatting

**seventhdr** · 02-13-2023, 09:28 PM - **1 Like**

I'm guessing that it was the SDM motor having difficulty moving the gears in the lens.

My understanding of the problem is that on a lot of the early SDM lenses there is a lubricant on the internal gears which gets more viscous (hard/thicker) with age and non use of the lens. At which point the SDM motor cannot generate enough torque to turn the gears against the viscous lubricant.

Periodically exercising the lens on the camera or manually on or off the cemera serves to loosen up the lubricant to the point where the torque generated by the SDM motor is now sufficient to turn the gears and focus the lens.

Your description seems to match this situation.

So use the lens frequently, or if you let it sit for mor ethan a week, exercise it by fitting it to a camera, manually turning the focus ring back and forth a couple of times and them AF with the lens. This should keep the lubricant from getting viscous to the point where the AF motor in the lens oes not have enough torque to turn the AF gears.

Regards

Chris

**EricBT** · 02-13-2023, 10:27 PM

Sounds like good advice. I'll give that a try!

**UncleVanya** · 02-13-2023, 10:43 PM - **1 Like**

While I’ve never seen that on my Pentax bodies. I have seen similar behavior (rarely) on my Sony A7riii using the Monster adapter LA-KE1 and some sdm lenses. The DA200 has locked manual focus up and refused to focus on occasion on the adapter. Cycling power usually resolves the issue. It may not be related but it might be…

sbc · 02-13-2023, 10:55 PM

Happened to mine many years ago. I think it was the gears. So now I would exercise the lens by turning the focusing ring manually off the camera. So far so good - fingers crossed.

alpheios · 02-14-2023, 03:39 AM

Mine shows the exact same symptoms. I give it some regular exercise to keep it working properly. I didn’t know it had to do with the grease though. Always thought it was maybe a capacitor that lost charge over time.

normhead · 02-14-2023, 06:05 AM - **1 Like**

MY DA*200 and DA* 60-250 both exhibit the same behaviour when they haven't been used for a while. It's been happening for years, I just put it on camera and wait until it works while trying the AF every now and then. eventually they come back to life. It is kind of interesting (in an annoying kind of way) that when the AF doesn't work, the quick shift also doesn't work.

bdery · 02-14-2023, 06:42 AM

Originally posted by normhead

It is kind of interesting (in an annoying kind of way) that when the AF doesn't work, the quick shift also doesn't work.

Correct, but switching to MF on the lens lets you focus. The few times it happened (after some months without use) just working the focus ring back and forth several times fixed it.

**UncleVanya** · 02-14-2023, 07:10 AM

Originally posted by bdery

Correct, but switching to MF on the lens lets you focus. The few times it happened (after some months without use) just working the focus ring back and forth several times fixed it.

On my Sony using the adapter this isn’t always true. Switching the power off is sometimes the only fix. It’s not common but it seems to be similar to what the op experienced.

normhead · 02-14-2023, 07:19 AM

Quote:

Correct, but switching to MF on the lens lets you focus.

Not on my two lenses. Switching to MF is the first thing I try.

bdery · 02-14-2023, 01:42 PM

Originally posted by UncleVanya

On my Sony using the adapter this isn’t always true. Switching the power off is sometimes the only fix. It’s not common but it seems to be similar to what the op experienced.

When it happened, I did turn off the camera before, I believe, but what made the difference was switching to MF on the lens.

Originally posted by normhead

Not on my two lenses. Switching to MF is the first thing I try.

On the camera or on the lens? I remember observing a difference.

normhead · 02-14-2023, 02:15 PM

Originally posted by bdery

When it happened, I did turn off the camera before, I believe, but what made the difference was switching to MF on the lens.

On the camera or on the lens? I remember observing a difference.

Usually on both, just to be sure.

**yucatanPentax** · 02-14-2023, 11:10 PM

I have a DA* 60-250mm and have followed the discussion over SDM through the years, mostly because that lens has no screw drive conversion option (as far as anyone has been able to discover so far).

My lens exhibits this behavior sometimes after non-usage, but it eventually begins to work. So I just try it out at home for awhile. Once working, it doesn't stop that same day or next. Having gone through this several times, my personal view isn't that the grease is congealed or become sticky, but tend toward views expressed by some in the past that "the motor needs to wake up." That may be more electrical than mechanical, but who knows.

I doubt it matters a whole lot what the issue actually is, as long as the lens "wakes up" or overcomes the grease or whatever, as long as it eventually begins to work fine. So far, mine has woken up, usually fairly quickly, with a few off-and-ons and a few turns of the focus ring.

bdery · 02-15-2023, 06:05 AM - **1 Like**

Originally posted by yucatanPentax

I have a DA* 60-250mm and have followed the discussion over SDM through the years, mostly because that lens has no screw drive conversion option (as far as anyone has been able to discover so far).

Indeed the only known workaround involves a Sony body:

Monster Adapter LA-KE1 Pentax K to Sony E Lens Adapter Review - Introduction | PentaxForums.com Reviews

02-13-2023, 08:36 PM	#1
EricBT Site Supporter Join Date: Jul 2016 Location: Melbourne Posts: 109	Strange Focus Problem with the 60-250mm Here's a focusing problem I found using the K3-III and the60-250mm. Trying out the lens today, after not using it for a while, it would not autofocus. The lens would make a slight squealing sound when trying to autofocus and the distance scale would only move slightly between the 2m and1.1m mark. The same behaviour occurred when I tried to use quick shift or by putting the lens focus switch to MF. Oddly enough, when I set the camera body focus switch to MF it would allow full manual focus. When I removed the lens from the camera I could also now get full distance scale movement using the focusing ring. I cleaned the contacts on both lens and body with no effect. There is no damage on the lens contacts and all seems physically OK. The K3-III has the latest firmware and I have not had any issues in the past with this lens. My first thought was SDM failure but the fact that it tried to autofocus, and that it would only manual focus using the camera body switch or when it is disconnected, was really odd. So I got out my old K3 and tried that. Autofocus was back working again. When I put the lens back on the K3-III full autofocus and manual focus were also working again. I don't know what caused the issue, I had a fully charged battery in the camera, but at least it's working now. Has anyone else had similar strange issues with this or other lenses? Last edited by EricBT; 02-13-2023 at 08:38 PM. Reason: Formatting

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02-13-2023, 09:28 PM - 1 Like	#2
seventhdr Site Supporter Join Date: Mar 2007 Location: Christchurch, New Zealand Photos: Gallery Posts: 1,440	I'm guessing that it was the SDM motor having difficulty moving the gears in the lens. My understanding of the problem is that on a lot of the early SDM lenses there is a lubricant on the internal gears which gets more viscous (hard/thicker) with age and non use of the lens. At which point the SDM motor cannot generate enough torque to turn the gears against the viscous lubricant. Periodically exercising the lens on the camera or manually on or off the cemera serves to loosen up the lubricant to the point where the torque generated by the SDM motor is now sufficient to turn the gears and focus the lens. Your description seems to match this situation. So use the lens frequently, or if you let it sit for mor ethan a week, exercise it by fitting it to a camera, manually turning the focus ring back and forth a couple of times and them AF with the lens. This should keep the lubricant from getting viscous to the point where the AF motor in the lens oes not have enough torque to turn the AF gears. Regards Chris

02-13-2023, 10:27 PM	#3
EricBT Site Supporter Join Date: Jul 2016 Location: Melbourne Posts: 109 Original Poster	Sounds like good advice. I'll give that a try!

02-13-2023, 10:43 PM - 1 Like	#4
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,412	While I’ve never seen that on my Pentax bodies. I have seen similar behavior (rarely) on my Sony A7riii using the Monster adapter LA-KE1 and some sdm lenses. The DA200 has locked manual focus up and refused to focus on occasion on the adapter. Cycling power usually resolves the issue. It may not be related but it might be…

02-13-2023, 10:55 PM	#5
sbc Pentaxian Join Date: Mar 2008 Photos: Albums Posts: 357	Happened to mine many years ago. I think it was the gears. So now I would exercise the lens by turning the focusing ring manually off the camera. So far so good - fingers crossed.

02-14-2023, 03:39 AM	#6
alpheios Pentaxian Join Date: Nov 2015 Location: Bremen Posts: 410	Mine shows the exact same symptoms. I give it some regular exercise to keep it working properly. I didn’t know it had to do with the grease though. Always thought it was maybe a capacitor that lost charge over time.

02-14-2023, 06:05 AM - 1 Like	#7
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	MY DA200 and DA 60-250 both exhibit the same behaviour when they haven't been used for a while. It's been happening for years, I just put it on camera and wait until it works while trying the AF every now and then. eventually they come back to life. It is kind of interesting (in an annoying kind of way) that when the AF doesn't work, the quick shift also doesn't work.

02-14-2023, 06:42 AM	#8
bdery Pentaxian Join Date: Mar 2008 Location: Quebec city, Canada Photos: Gallery Posts: 9,357	Originally posted by normhead It is kind of interesting (in an annoying kind of way) that when the AF doesn't work, the quick shift also doesn't work. Correct, but switching to MF on the lens lets you focus. The few times it happened (after some months without use) just working the focus ring back and forth several times fixed it.

02-14-2023, 07:10 AM	#9
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,412	Originally posted by bdery Correct, but switching to MF on the lens lets you focus. The few times it happened (after some months without use) just working the focus ring back and forth several times fixed it. On my Sony using the adapter this isn’t always true. Switching the power off is sometimes the only fix. It’s not common but it seems to be similar to what the op experienced.

02-14-2023, 07:19 AM	#10
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Quote: Correct, but switching to MF on the lens lets you focus. Not on my two lenses. Switching to MF is the first thing I try.

02-14-2023, 01:42 PM	#11
bdery Pentaxian Join Date: Mar 2008 Location: Quebec city, Canada Photos: Gallery Posts: 9,357	Originally posted by UncleVanya On my Sony using the adapter this isn’t always true. Switching the power off is sometimes the only fix. It’s not common but it seems to be similar to what the op experienced. When it happened, I did turn off the camera before, I believe, but what made the difference was switching to MF on the lens. Originally posted by normhead Not on my two lenses. Switching to MF is the first thing I try. On the camera or on the lens? I remember observing a difference.

02-14-2023, 02:15 PM	#12
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Originally posted by bdery When it happened, I did turn off the camera before, I believe, but what made the difference was switching to MF on the lens. On the camera or on the lens? I remember observing a difference. Usually on both, just to be sure.

02-14-2023, 11:10 PM	#13
yucatanPentax Loyal Site Supporter Join Date: Dec 2009 Location: Dallas / Yucatan Posts: 1,841	I have a DA* 60-250mm and have followed the discussion over SDM through the years, mostly because that lens has no screw drive conversion option (as far as anyone has been able to discover so far). My lens exhibits this behavior sometimes after non-usage, but it eventually begins to work. So I just try it out at home for awhile. Once working, it doesn't stop that same day or next. Having gone through this several times, my personal view isn't that the grease is congealed or become sticky, but tend toward views expressed by some in the past that "the motor needs to wake up." That may be more electrical than mechanical, but who knows. I doubt it matters a whole lot what the issue actually is, as long as the lens "wakes up" or overcomes the grease or whatever, as long as it eventually begins to work fine. So far, mine has woken up, usually fairly quickly, with a few off-and-ons and a few turns of the focus ring.

02-15-2023, 06:05 AM - 1 Like	#14
bdery Pentaxian Join Date: Mar 2008 Location: Quebec city, Canada Photos: Gallery Posts: 9,357	Originally posted by yucatanPentax I have a DA* 60-250mm and have followed the discussion over SDM through the years, mostly because that lens has no screw drive conversion option (as far as anyone has been able to discover so far). Indeed the only known workaround involves a Sony body: Monster Adapter LA-KE1 Pentax K to Sony E Lens Adapter Review - Introduction \| PentaxForums.com Reviews