[Fabulozzz]

Hi all!
My Pentax K10d has me puzzled.... works with every lens i own, except my 17-70mm 2.8-4.5 and 24-70mm 2.8 Sigma zooms.

That is, whenever i install either of these lenses, my K10d does not show the F stop and AF does not work. I can still use the 24-70mm with the aperture ring, but the 17-70 does not have an aperture ring and is absolutely useless.

I tried the 17-70 on a K20d and it works fine. Both lenses work on my old MZ-M in program mode as well.

But, my K10d works fine with my DA12-24, F50 1.7, A setting on all my manual focus lenses, including KA mount Adaptalls. Even works with my Sigma 70-300.

I am puzzled!!! I am afraid that if i send the camera for service, i will just lose the camera for a month and it will come back with the same problem.... and service charges.

Has anyone had the same issue???

[Lowell Goudge]

it sounds like a contact problem with the lens and camera.

You can clean the contacts with an eraser and you can also turn the lens back and fourth a little on the mount to see if the contacts pick up.

[Fabulozzz]

it sounds like a contact problem with the lens and camera.

You can clean the contacts with an eraser and you can also turn the lens back and fourth a little on the mount to see if the contacts pick up.

Already tried that. Did the eraser trick on both lens and body. And moving the lens has no effect.

[Lowell Goudge]

if it is only AF then it is pin 7 (furthest away from the lens locking pin that is giving you a problem, I suspect.

still may be contacts but it is unusual

I have not coem across this before and both my sigmas work on all 4 of my AF bodies (PZ-1, *istD, K10D and K7)

[Fabulozzz]

Playing around with the camera, found something interesting about using the aperture VS my problem

I normally use my K10d with "Using Aperture Ring" set to "Allowed". This way i can use my old lenses and only my two newer Sigma zooms do not work... but used to work just a few weeks ago.

As a test, i changed "Using Aperture Ring" to "Prohibited". Now, NOTHING WORKS!!! Not even my Pentax AF lenses. Shutter does not release.

Changed setting back to "Allowed" and now my lenses work.... except for the 2 Sigmas.

What the f... ?!?!?!

[mazdamazda]

Have you updated your K10D's firrmware to v1.3 to enable the use of SDM (or Sigma's HSM) equipped lens?

If you're still using v1.1, your SDM / HSM equipped lens will not AF (as what you've mentioned).

[Fabulozzz]

already running firmware v1.3.... and my Sigmas are camera driven AF, not sdm or hsm. Besides, when "Using Aperture Ring" is set to "Prohibited", even my Pentax-A manual focuses lenses do not work, shutter won't release.

[Lowell Goudge]

already running firmware v1.3.... and my Sigmas are camera driven AF, not sdm or hsm. Besides, when "Using Aperture Ring" is set to "Prohibited", even my Pentax-A manual focuses lenses do not work, shutter won't release.

This is interesting?

note that when the use aperture ring is set to prohibited, it means that the lenses MUST be in the A position to function. Otherwise you cannot release the shutter.

This means to me that you have a problem with the camera body reading the A position, or you are attempting to use the lenses in other than A mode.

The lenses MUST be in a mode if the Use aperture ring is set to prohibited.

[Fabulozzz]

Thanks Lowell, but i already know all this about the "A" setting. I am using Pentax DSLRs since 2006 and I read the manuals... believe it or not ;-) ... i am also using Pentax equipment since i was 16... and i am 46 now. I am a computer technician and troubleshooting is my job. I did my homeworks before posting here. I want to try every solution available before i send the camera in for repair.... service is out of town and i would lose the camera for 4-6 weeks, wich is not acceptable to me since i do not have another DSLR and don't want to shoot 35mm.

Forget about all other lenses, i will test with only the Sigma 17-70 & Pentax 12-24.
Neither of them has an aperture ring.

With "Using Aperture Ring" set to "Allowed", the Pentax works, but the Sigma does not focus, does not communicate aperture and shutter does not release.

With "Using Aperture Ring" set to "Prohibited", both lenses do not work, just like trying to use an old PK lens.

So i am puzzled. Makes no sense to me that the Pentax lens works and not the Sigma, both are using the camera driven AF.

Since the camera works, except with the 2 Sigmas, i am tempted to buy a 2nd K10d used body instead of repairing.... at least $100 for repair if not parts required... would probably be more like $150-200 ... can get a K10d used body under $400 and keep the "funny" one as a backup.

[Lowell Goudge]

I have gone back through and re-read all the comments.

Individually, and please correct me if I am wrong.
-the sigma lenses work on every other body you have, just not the K10D

- and all your other lenses work on all your bodies as they should.

I am very confused about your statement that if you prohibit aperture ring even your SMC-A lenses dont work. But you tell me to ignore this point, but this point may be key.

If the facts are as above, and you have a problem even with you r KA mounts, then maybe the problem is a poor spring in the K10D body on the "A" setting pin. Third from the lens locking pin. This pin is deliberately recessed because on K mounts it CANNOT touch the lens base. SHorting this pin to the lens base is exactly what the "A" function on the lens does.

If this pin is failed and too recessed, then the KA mounts, which are a sliding pin that gets pushed out to contact this pin, and your 2 sigmas may not extend far enough to make the camera work correctly.

To test this theory, put a little tinfoil over this pin only, and attach the lenses in question, if the camera works it is a mechanical problem with the pin in the lens mount, if it does not work then I am at a loss because it cannot be any of the remaining circuitry since all your other lenses function. To me, with all the symptoms you have, the camera side contact is recessed too far.

[GeneV]

I have gone back through and re-read all the comments.

Individually, and please correct me if I am wrong.
-the sigma lenses work on every other body you have, just not the K10D

- and all your other lenses work on all your bodies as they should.

I am very confused about your statement that if you prohibit aperture ring even your SMC-A lenses dont work. But you tell me to ignore this point, but this point may be key.

If the facts are as above, and you have a problem even with you r KA mounts, then maybe the problem is a poor spring in the K10D body on the "A" setting pin. Third from the lens locking pin. This pin is deliberately recessed because on K mounts it CANNOT touch the lens base. SHorting this pin to the lens base is exactly what the "A" function on the lens does.

If this pin is failed and too recessed, then the KA mounts, which are a sliding pin that gets pushed out to contact this pin, and your 2 sigmas may not extend far enough to make the camera work correctly.

To test this theory, put a little tinfoil over this pin only, and attach the lenses in question, if the camera works it is a mechanical problem with the pin in the lens mount, if it does not work then I am at a loss because it cannot be any of the remaining circuitry since all your other lenses function. To me, with all the symptoms you have, the camera side contact is recessed too far.

I had exactly this problem with a used "A" lens (rather than the camera body), and the foil trick worked. I sent it back. Luckily I bought it from KEH, who were very nice about it.

[Fabulozzz]

Just tried the foil trick over the 3rd contact from the locking pin...... not working. My camera does not like Sigma lenses.
Even flashed the camera again with firmware v1.3 and reset the custom settings.
I am afraid that if i send my camera for repair it will come back with the same behavior.... might as well invest my money in another body and keep this one to use with Pentax and Tamron lenses only.... even my KA Adaptall lenses work on it. That camera just does not like Sigmas. And i don't care about the "Prohibited" setting not working for "Using Aperture Ring" as i don't use it, always use "Permitted"
If only the Sigmas were cheapies.... but my only cheap Sigma works fine, a 70-300mm. The 24-70mm F/2.8 is an EX and the 17-70mm is a lot better than the Pentax kit lens... wich i sold.
I am puzzled....

[Lowell Goudge]

when you say not working what does the camera do?

shorting the third pin should make it think there is an A lens.

try both the 3rd and 7th just to make sure.

But shorting the 7th will cost you AF.

It is strange, I have not heard this complaint from any other isgma owners.

we have several who use the 24-70.

did you purchase the lenses and cameras new?

[Fabulozzz]

when you say not working what does the camera do?

Camera works the same with and without the foil.
Camera and Sigma 24-70 were purchased used 1 year ago.
Camera was working ok but Sigma has been service for a loose front assembly and it came back with a problem with the aperture ring, has been serviced again... good thing it's an EX under warranty.

The 17-70mm was purchase 1½ year ago and never had any issues. This lens was tested on a MZ-M 35mm and a brand new K20d and it works fine.

Anyhow, i already started shopping for a used K10d or K20d body. I would love a new K7.... but $$$$$$$

[Wheatfield]

Another SIG-nificant MA-lfunction.
I hate their junk.