HD D FA 28-105/3.5-5.6 occasionally refuses to focus on K-1

shyrsio · 10-23-2020, 06:32 AM

Hello,
I have been enjoying my K-1 for some time now but this issue is starting to bug me: once in a while it wont focus on the target it wont even try, but when I move slightly the zoom ring it seems to awaken and it locks on focus as usually.
Now, when I first bought my used K-1 I did notice some kind of play on the zoom ring. It seems like it runs for 1 mm freely before the dumping engages. Otherwise the zoom ring doesn't have any play in any direction. The problem was very occasional at first but its starting to show up quite often lately.
I have tested the D FA 28-105 on my K-5 and have yet to encounter the flaw, strange!
What I suspect is a bad contact on the lens that inhibits the camera to know the exact focal value to focus. perhaps the "play" on the zoom ring does this, since when i move it, it engages.
I love this "kit lens", If we can really call it that! I don't know what to do.

Any opinion on your side is appreciated!
Thanks!

Unregistered User · 10-23-2020, 07:10 AM

Originally posted by shyrsio

Hello,
I have been enjoying my K-1 for some time now but this issue is starting to bug me: once in a while it wont focus on the target it wont even try, but when I move slightly the zoom ring it seems to awaken and it locks on focus as usually.
Now, when I first bought my used K-1 I did notice some kind of play on the zoom ring. It seems like it runs for 1 mm freely before the dumping engages. Otherwise the zoom ring doesn't have any play in any direction. The problem was very occasional at first but its starting to show up quite often lately.
I have tested the D FA 28-105 on my K-5 and have yet to encounter the flaw, strange!
What I suspect is a bad contact on the lens that inhibits the camera to know the exact focal value to focus. perhaps the "play" on the zoom ring does this, since when i move it, it engages.
I love this "kit lens", If we can really call it that! I don't know what to do.

Any opinion on your side is appreciated!
Thanks!

If you do not encounter the flaw with the K-5 I think it is the K-1 you should blame. Perhaps a bad contact on the body is more likely than on the lens. Thoroughly clean the contact of both lens and body and see what happens.

shyrsio · 10-23-2020, 03:39 PM

Originally posted by AfterPentax

If you do not encounter the flaw with the K-5 I think it is the K-1 you should blame. Perhaps a bad contact on the body is more likely than on the lens. Thoroughly clean the contact of both lens and body and see what happens.

I did some extensive testing with the K-5, I get the same problem. I seem to have narrowed it down to the wobble, it does focus on one end of it but not on the other.

10-23-2020, 06:32 AM	#1
shyrsio Pentaxian Join Date: Apr 2016 Location: Tirana Posts: 780	HD D FA 28-105/3.5-5.6 occasionally refuses to focus on K-1 Hello, I have been enjoying my K-1 for some time now but this issue is starting to bug me: once in a while it wont focus on the target it wont even try, but when I move slightly the zoom ring it seems to awaken and it locks on focus as usually. Now, when I first bought my used K-1 I did notice some kind of play on the zoom ring. It seems like it runs for 1 mm freely before the dumping engages. Otherwise the zoom ring doesn't have any play in any direction. The problem was very occasional at first but its starting to show up quite often lately. I have tested the D FA 28-105 on my K-5 and have yet to encounter the flaw, strange! What I suspect is a bad contact on the lens that inhibits the camera to know the exact focal value to focus. perhaps the "play" on the zoom ring does this, since when i move it, it engages. I love this "kit lens", If we can really call it that! I don't know what to do. Any opinion on your side is appreciated! Thanks!

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10-23-2020, 07:10 AM	#2
Unregistered User Guest	Originally posted by shyrsio Hello, I have been enjoying my K-1 for some time now but this issue is starting to bug me: once in a while it wont focus on the target it wont even try, but when I move slightly the zoom ring it seems to awaken and it locks on focus as usually. Now, when I first bought my used K-1 I did notice some kind of play on the zoom ring. It seems like it runs for 1 mm freely before the dumping engages. Otherwise the zoom ring doesn't have any play in any direction. The problem was very occasional at first but its starting to show up quite often lately. I have tested the D FA 28-105 on my K-5 and have yet to encounter the flaw, strange! What I suspect is a bad contact on the lens that inhibits the camera to know the exact focal value to focus. perhaps the "play" on the zoom ring does this, since when i move it, it engages. I love this "kit lens", If we can really call it that! I don't know what to do. Any opinion on your side is appreciated! Thanks! If you do not encounter the flaw with the K-5 I think it is the K-1 you should blame. Perhaps a bad contact on the body is more likely than on the lens. Thoroughly clean the contact of both lens and body and see what happens.

10-23-2020, 03:39 PM	#3
shyrsio Pentaxian Join Date: Apr 2016 Location: Tirana Posts: 780 Original Poster	Originally posted by AfterPentax If you do not encounter the flaw with the K-5 I think it is the K-1 you should blame. Perhaps a bad contact on the body is more likely than on the lens. Thoroughly clean the contact of both lens and body and see what happens. I did some extensive testing with the K-5, I get the same problem. I seem to have narrowed it down to the wobble, it does focus on one end of it but not on the other.