[Quich]

Hello everyone,

I recently got a used (but near new) HD Pentax-DA 1.4x AW.
I have a first hand K3 and a first hand 60-250, among other lenses.

When the Pentax TC is coupled with the 60-250, there is a strange behavior of the manual focus ring / quick shift.
It does it when the couple is mounted on the K3 body, whatever is the position of the AF/MF switch on the body and on the lens, but also when the TC is just mounted on the lens, without being attached to the camera body.
The focus ring to go from minimum focus distance to maximum focus distance is not fluid. It's like it's blocking into something at some points, it gets harder on a small section and gets normal and harder and normal, etc. Sometimes, the ring is even rotating without moving the focus lenses at all, the distance indicator not moving. It more or less depends on the pointing direction of the lens (ground, horizontal, sky) but it does it all the time. It body not depend on the zoom position.
To go from max focus to min is fluid.
AF with SDM is working fine in both phase and contrast detection when attached to the camera body (with TC).

There is no problem when the lens is alone (without TC), mounted or not on the K3, whatever is the pointing or zoom position.
No problem either when coupled with a promaster spectrum 7 1.7x TC mounted or not on the K3. (SDM AF is hunting with phase detection, working with contrast detection in live view, but the manual focus is always working well).

Has anyone encountered this kind of troubles? I did not find similar problems.
What could be the reason?
I was maybe thinking of some air that could not escape as it should due to the WR of both the lens and TC. But the zoom ring feels more or less the same with or without the TC, and it should have more influence (although it is much harder to rotate than the focus ring, and so the difference might not be noticeable).

[Ole]

Sounds like a problem with the gear shaft in the TC, perhaps it is be bent a bit?

[Quich]

Hello Ole, thank you for the suggestion.

What I don't get is that the gear shaft does not move, as I think it is not supposed to (SDM lens).
When the 60-250 is alone (not mounted, no TC) and if I rotate the focus ring, the shaft does not rotate. Should it?

I have no trouble with the focus ring of a Pentax 100mm Macro WR that use the gear shaft when coupled with the TC 1.4x (even when using both 1.4x and 1.7x TC). So I think the shaft extension of the TC is fine.

---------- Post added 12-27-15 at 05:15 AM ----------

But the 100 macro has also quick shift so the shaft does not rotate when using the focus ring.
I tried with a DA 50 F1.8 mounted on the TC 1.4x, no problem, the shaft of the TC is moving and everything is fluid.

[MikeD]

I have the 1.4 tc and have used it with all my lenses and did not experience what you describe 18-55wr, 17-50 tamron, 90mm tamron, 60-250

[Scorpio71GR]

I use my 60-250 with my Tamron 1.4TC and have not had any issues yet. It sounds like the 60-250 and the TC are not cominucating properly. The ring motor has to disengage to allow manual focus. Does your K3 have the latest Firmware? The K3 needed a firmware update to use the HD TC I believe.

[Quich]

My K3 has 1.21 firmware.
But the problem also happens when everything is not mounted on the camera.
When the 60-250 is mounted on the Pentax TC and not mounted on the camera (so I can see), the shaft if the TC is not rotating when I move the focus ring, but it is not fluid.

I will try to upload a video but I have a very low upload datarate here so it may take time.

---------- Post added 12-27-15 at 07:05 AM ----------

I have no idea why, but it started working normaly when I tried to record it.
I tried several couple of TC / lens yesterday and it was doing it everytime with the Pentax TC (I first notice when trying to take a picture in my house).
If it happens again I will be sure to record it.

[Scorpio71GR]

I am not an expert but it sounds like the screwdrive is engaged for some reason. I have no idea why it would do that, but the 60-250 will focus with both SDM and screwdrive.

[Quich]

The lens are quite hard to put on the TC, as if it was locking closer than the camera mount.
The problem on the 60-250 reproducted itself when using tightly a non pentax rear cap, and I recorded it.
I am uploading the video on youtube, it will take some time.

---------- Post added 12-27-15 at 08:07 AM ----------

Lenses*
2 hours upload time...

[Quich]

Video showing the problem is there :

Youtu.be

Youtu.be

---------- Post added 12-27-15 at 10:26 AM ----------

I was also wondering if it is normal that I can still see the aperture blades when I am putting max aperture at 60mm. It is like they are not fully retracted.
On my others lenses, at max aperture the blades are not visible anymore (or just a little bit), whatever the focal length.

[Quich]

Anyone?

[Scorpio71GR]

Sorry I have no idea what is happening therd. Maybe you could try to repost in the Troubleshooting Section. You may get better responses there.

[Quich]

Thank you, I posted there: https://www.pentaxforums.com/forums/58-troubleshooting-beginner-help/310639-f...-rear-cap.html