[Buffy]

Hello,

I recently sold my Sigma 170-500mm APO (non-DG) lens to Pentax user overseas. He wrote to me to say it arrived in good condition but does not work on his K10D, and his local camera shop tells him that older Sigma lens are not compatible with digital K-series cameras. I told him that was absurd and to make sure the aperture ring was in the "A" position.

Is there anything else that might be necessary?

[Wethphotography]

I recall several threads earlier this year about users having to have some sigma products "rechipped" to work with the K10d. I do not know what that involves or if it applies to your situation. Here is a link about this from a Canon users forum.
Filter, Bags, Tripods and Accessories Forum: rechipping sigma lens - photo.net
Maybe someone else will know more. Best wishes.

[Jonas B]

I recall several threads earlier this year about users having to have some sigma products "rechipped" to work with the K10d. I do not know what that involves or if it applies to your situation.

What? Sigma sells flashes that can be rechipped but I have never heard of a rechipped lens for Pentax? Do you recall any details (not Canon related I mean)?

[Wethphotography]

What? Sigma sells flashes that can be rechipped but I have never heard of a rechipped lens for Pentax? Do you recall any details (not Canon related I mean)?

Jonas,
It might be the flashes that I was recalling. Unfortunately, I do not remember any details. My guess is that I am way off on this....... Hopefully someone more knowledgable than I will post to help with the original question.

[Jonas B]

-snip-
My guess is that I am way off on this.......

That's ok - it makes me feel less lonely.

regards,

[NaClH2O]

Hi Buffy
Also make sure that he knows to have the aperture ring "allowed" in the Custom menu (option 2, I believe)

edit oops, read the post more carefully, obviously the lens is an auto aperture lens. In this case "the jury will disregard the above comments"
The other thing I would check are dirty contacts on lens and body and to be sure the lens is firmly mounted.

NaCl(I have no idea why that is not the default choice)H2O

[egordon99]

You don't need to do this if you keep the aperture ring on 'A'

Hi Buffy
Also make sure that he knows to have the aperture ring "allowed" in the Custom menu (option 2, I believe)

NaCl(I have no idea why that is not the default choice)H2O

[WildSioux]

You don't need to do this if you keep the aperture ring on 'A'

Actually on some you do...For instance, on my K10D with the Sigma 24-135 lens I got a few months ago. Without changing the aperture ring setting to "2" in the custom menu, the camera would just turn on and flash the screen for a little bit then just not respond. This was regardless of setting the lens to A. So the only way to work around it was to set the custom menu aperture ring to 2.

Weird thing is, this was a few months ago when it was cold. now that it is warm out the camera works fine with the lens and the aperture setting to 1.

[Classvino]

...his local camera shop tells him that older Sigma lens are not compatible with digital K-series cameras. . I told him that was absurd....

You're right - it is totally absurd.

One of Pentax's biggest "pluses" is the fact that any Pentax glass will work with their new D bodies, and since the "K-contacts" that worked on the older bodies are the same for Pentax and Sigma, one would think that the statement could also be extended to the Sigma K-mount offerings...

I have used 6 or 7 Sigma lenses on my K10D and they all work fine. No settings changes were required on my camera, though all of the lenses I've used were either on 'A' or had no Aperture ring... I've since changed the "Allow Ap. Ring" setting to allow me to use an old Pentax M lens, but the Sigma's I tried worked before AND after the setting change.

YMMV