SMC Pentax-DA 21mm F/3.2 AL Focus Problem

leigh8904 · 10-03-2015, 11:54 PM

Hi,

I have a problem with my SMC Pentax-DA 21mm F/3.2 AL, basically the focus range is "offset" from what it should be. The focus range is supposed to be 20cm to infinity, but as of about one week ago, mine now appears to have a focus range from 10cm - 70cm. I also tried autofocus to line up with the 1.3m on the focus scale, and that was achieved at about 26cm subject distance. With autofocus, I cannot focus on anything more distant than about 70cm! To see the problem, look at https://freeshell.de/~lwedding/20151004-IM5045.jpg. This photo was taken with focus set to infinity on the lens; the red/orange rubber boot on the right hand side is about 70cm from camera, the end of the timber deck is about 3.5m.

Up to about 1 week earlier, it was working fine: see https://freeshell.de/~lwedding/20150926-IM4906.jpg.

Has anyone seen this type of problem before? Would it be costly to get repaired?

Camera is Pentax K-m. I tried a few other lenses on the camera, and they all focus fine.

Thanks.

Jonathan Mac · 10-04-2015, 12:23 AM

I can't tell you about cost but it will certainly need to be repaired.

johnhilvert · 10-04-2015, 12:37 AM

Just a hunch. The K-m has been dogged with a clunky auto-focus system.

According to a review in Pentax K2000 / K-m Review: Digital Photography Review the active point is always automatically selected without any indication given as to which one has been used. It suggests a work around to lock the camera to use its central AF-point, and use it as a single AF-point camera but at least you know which point is the focus point.

The other thing to try before sending it in for repair is to check and clean the contacts on the lens to see if that helps.

**grahame** · 10-04-2015, 06:45 AM

It sounds the lens "self-disassembled" itself. search for the past threads you should be able to see same issue.
The two focus helicoid ring mis-engaged and the front parts moves away from the mount end. at first you lose focus to infinity, and finally the lens might separate by itself into two pieces.
DA 70 also has similar problem.
it needs to be fixed.

leigh8904 · 10-04-2015, 12:51 PM

Originally posted by johnhilvert

According to a review in Pentax K2000 / K-m Review: Digital Photography Review the active point is always automatically selected without any indication given as to which one has been used. It suggests a work around to lock the camera to use its central AF-point, and use it as a single AF-point camera but at least you know which point is the focus point.

Thanks for the tip. It has happened to me on some occasions that the camera did not focus on what I had intended! I will give the single AF-point a try.

zapp · 10-06-2015, 10:43 PM

Typical probelm of the DA21. I had mine adjusted in a shop twice for the same reason. The focusing mechanism gets lose and you cannot focus to infinity anymore. There are instructions on the web how to fix it yourself or spend something like 70 bucks in a repair shop.

leigh8904 · 10-27-2015, 02:34 AM

Just to follow up: I discovered lens was still under warranty from KEH, and they exchanged it for another one which is now working fine. Excellent service from KEH.

10-03-2015, 11:54 PM	#1
leigh8904 New Member Join Date: Oct 2015 Posts: 4	SMC Pentax-DA 21mm F/3.2 AL Focus Problem Hi, I have a problem with my SMC Pentax-DA 21mm F/3.2 AL, basically the focus range is "offset" from what it should be. The focus range is supposed to be 20cm to infinity, but as of about one week ago, mine now appears to have a focus range from 10cm - 70cm. I also tried autofocus to line up with the 1.3m on the focus scale, and that was achieved at about 26cm subject distance. With autofocus, I cannot focus on anything more distant than about 70cm! To see the problem, look at https://freeshell.de/~lwedding/20151004-IM5045.jpg. This photo was taken with focus set to infinity on the lens; the red/orange rubber boot on the right hand side is about 70cm from camera, the end of the timber deck is about 3.5m. Up to about 1 week earlier, it was working fine: see https://freeshell.de/~lwedding/20150926-IM4906.jpg. Has anyone seen this type of problem before? Would it be costly to get repaired? Camera is Pentax K-m. I tried a few other lenses on the camera, and they all focus fine. Thanks.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
For Sale - Sold: Pentax SMC DA 21mm f/3.2 AL Limited black in EU (Worldwide)	andersju	Sold Items	2	07-04-2011 12:23 PM
For Sale - Sold: Pentax smc DA 21mm f/3,2 AL Limited + extras (EUR)	radora	Sold Items	2	11-16-2010 03:06 PM

10-04-2015, 12:23 AM	#2
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,894	I can't tell you about cost but it will certainly need to be repaired.

10-04-2015, 12:37 AM	#3
johnhilvert Senior Member Join Date: May 2015 Location: Canberra, ACT Posts: 245	Just a hunch. The K-m has been dogged with a clunky auto-focus system. According to a review in Pentax K2000 / K-m Review: Digital Photography Review the active point is always automatically selected without any indication given as to which one has been used. It suggests a work around to lock the camera to use its central AF-point, and use it as a single AF-point camera but at least you know which point is the focus point. The other thing to try before sending it in for repair is to check and clean the contacts on the lens to see if that helps.

10-04-2015, 06:45 AM	#4
grahame Loyal Site Supporter Join Date: Aug 2011 Photos: Albums Posts: 2,041	It sounds the lens "self-disassembled" itself. search for the past threads you should be able to see same issue. The two focus helicoid ring mis-engaged and the front parts moves away from the mount end. at first you lose focus to infinity, and finally the lens might separate by itself into two pieces. DA 70 also has similar problem. it needs to be fixed.

10-04-2015, 12:51 PM	#5
leigh8904 New Member Join Date: Oct 2015 Posts: 4 Original Poster	Originally posted by johnhilvert According to a review in Pentax K2000 / K-m Review: Digital Photography Review the active point is always automatically selected without any indication given as to which one has been used. It suggests a work around to lock the camera to use its central AF-point, and use it as a single AF-point camera but at least you know which point is the focus point. Thanks for the tip. It has happened to me on some occasions that the camera did not focus on what I had intended! I will give the single AF-point a try.

10-06-2015, 10:43 PM	#6
zapp Pentaxian Join Date: Jul 2011 Posts: 2,385	Typical probelm of the DA21. I had mine adjusted in a shop twice for the same reason. The focusing mechanism gets lose and you cannot focus to infinity anymore. There are instructions on the web how to fix it yourself or spend something like 70 bucks in a repair shop.

10-27-2015, 02:34 AM	#7
leigh8904 New Member Join Date: Oct 2015 Posts: 4 Original Poster	Just to follow up: I discovered lens was still under warranty from KEH, and they exchanged it for another one which is now working fine. Excellent service from KEH.