DA* 50-135...chasing focus issue

**simple1** · 02-20-2010, 04:28 PM

All,
My 2 year old 50/135 has started doing some weird back/front focus stuff.
Most of my shots were appearing to be OOF so I tested for FF/BF.
Testing on a tripod w/remote and SR off, at 135mm I found that I had to set AF adjustment to +7 to get a sharp in focus shot. Tried this from f2.8-4.5 and it was consistent. Distances tested were 30 ft and 15 ft.
I took several pictures in bright daylight and they were all in focus. From 3.5 ft thru 40 ft they were all fine.
Then while taking pictures in shade I found they were all OOF again. So I tested in the shade and found I had to set AF adjustment to -8. this was also tested at 135mm, f2.8-4.5 and distance of 4 ft.
So...next day I am taking pictures in sunlight and they are OOF again! This time I just adjusted on the fly and at AF adjustment +9 they were fine.
This is on a K7. I've tried 3 different fully charged batteries and cleaned the contacts.
On K10d I cannot get any in focus shots unless I focus manually.
I have a Tamron and Sigma lens that both focus fine so I am inclined to think it is the lens.
If anyone else has experienced something similar I'd appreciate their input.
Thanks in advance.
Mas

tlwyse · 02-21-2010, 09:02 PM

Just wait until your SDM craps out with that lens and your focus issues will disappear.

My 50-135 started acting up after about 7-8 months (wouldn't work for a few minutes and then would "wake up" and work the rest of the shoot).....went to use it last month and the SDM appears to completely dead now...2 months out of warranty. Sucks.

I'm now on a mission to AVOID any Pentax SDM-equipped lenses, even it means turning to 3rd party lenses. Thoroughly disgusted with my Pentax gear right now.

Terry

**simple1** · 02-22-2010, 09:09 AM

Terry,

Thanks for the reply. Sorry to hear about the issues.

For this lens I'm trying to get feedback on sending it for service, which is what I think it needs. While I tried to eliminate any error on my part, I am a novice - hence my post.

I wasn't really aware of the SDM issues until I started forum scouring looking for a problem similar to mine. If nothing else Pentax needs to acknowledge and address the concern. Either with data to show an acceptable failure rate, or with a solution.

The DA*60-250 I was leaning heavily toward getting, I am now hesitant about. I can't afford $1,000 for a disposable lens.

02-20-2010, 04:28 PM	#1
simple1 Loyal Site Supporter Join Date: Dec 2009 Location: In the Florida swamps Posts: 771	*DA 50-135...chasing focus issue** All, My 2 year old 50/135 has started doing some weird back/front focus stuff. Most of my shots were appearing to be OOF so I tested for FF/BF. Testing on a tripod w/remote and SR off, at 135mm I found that I had to set AF adjustment to +7 to get a sharp in focus shot. Tried this from f2.8-4.5 and it was consistent. Distances tested were 30 ft and 15 ft. I took several pictures in bright daylight and they were all in focus. From 3.5 ft thru 40 ft they were all fine. Then while taking pictures in shade I found they were all OOF again. So I tested in the shade and found I had to set AF adjustment to -8. this was also tested at 135mm, f2.8-4.5 and distance of 4 ft. So...next day I am taking pictures in sunlight and they are OOF again! This time I just adjusted on the fly and at AF adjustment +9 they were fine. This is on a K7. I've tried 3 different fully charged batteries and cleaned the contacts. On K10d I cannot get any in focus shots unless I focus manually. I have a Tamron and Sigma lens that both focus fine so I am inclined to think it is the lens. If anyone else has experienced something similar I'd appreciate their input. Thanks in advance. Mas

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02-21-2010, 09:02 PM	#2
tlwyse Senior Member Join Date: Aug 2008 Location: Waxhaw, NC, USA Photos: Gallery \| Albums Posts: 211	Just wait until your SDM craps out with that lens and your focus issues will disappear. My 50-135 started acting up after about 7-8 months (wouldn't work for a few minutes and then would "wake up" and work the rest of the shoot).....went to use it last month and the SDM appears to completely dead now...2 months out of warranty. Sucks. I'm now on a mission to AVOID any Pentax SDM-equipped lenses, even it means turning to 3rd party lenses. Thoroughly disgusted with my Pentax gear right now. Terry

02-22-2010, 09:09 AM	#3
simple1 Loyal Site Supporter Join Date: Dec 2009 Location: In the Florida swamps Posts: 771 Original Poster	Terry, Thanks for the reply. Sorry to hear about the issues. For this lens I'm trying to get feedback on sending it for service, which is what I think it needs. While I tried to eliminate any error on my part, I am a novice - hence my post. I wasn't really aware of the SDM issues until I started forum scouring looking for a problem similar to mine. If nothing else Pentax needs to acknowledge and address the concern. Either with data to show an acceptable failure rate, or with a solution. The DA*60-250 I was leaning heavily toward getting, I am now hesitant about. I can't afford $1,000 for a disposable lens.