[afrayssi]

Hi all and sorry for my poor english from France...

I bought this lens new 10years ago but i was a newbie and i thought the fault was becaus of my K10D so no warraty now

I read this thread
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/288879-sigm...s-problem.html

Now i'm sure I have the same problem: open at 7.1 i can correct with my k-3ii. Under it's impossible.
Sigma France desn't want to repair it, i have the old batch (like it's said in the post )
So i'm very frustrated.


Now i saw this thread:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/208353-how-...m-f-2-8-a.html

and i had an idea (may be stupid?): is there anybody with this lens without any focus problem and the k10d who can send me the eeprom of the good lens?
i would like to try to inject good eeprom in my lens...

It's stupid? Have i a chance to have a good lens? Somebody have try to do this?

Thank's a lot for your answers!!!

[VoiceOfReason]

I don't think you can reload firmware on the lens. I had one and with my K3 I required -4 with it, and -3 with my K1. If it is more than -10 since - values are what you use for backfocus then you may have to see if a repair shop will do a calibration of the lens to your camera. I am not sure if you have Sigma authorized independent shops, but is it worth a try even if it costs you a bit.

[aleonx3]

I don't think you can reload firmware on the lens. I had one and with my K3 I required -4 with it, and -3 with my K1. If it is more than -10 since - values are what you use for backfocus then you may have to see if a repair shop will do a calibration of the lens to your camera. I am not sure if you have Sigma authorized independent shops, but is it worth a try even if it costs you a bit.

+1, most likely a calibration issue which can be done on the lens (at your cost if it is out of warranty).

[nomadkng]

Hi all and sorry for my poor english from France...

I bought this lens new 10years ago but i was a newbie and i thought the fault was becaus of my K10D so no warraty now

I read this thread
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/288879-sigm...s-problem.html

Now i'm sure I have the same problem: open at 7.1 i can correct with my k-3ii. Under it's impossible.
Sigma France desn't want to repair it, i have the old batch (like it's said in the post )
So i'm very frustrated.


Now i saw this thread:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/208353-how-...m-f-2-8-a.html

and i had an idea (may be stupid?): is there anybody with this lens without any focus problem and the k10d who can send me the eeprom of the good lens?
i would like to try to inject good eeprom in my lens...

It's stupid? Have i a chance to have a good lens? Somebody have try to do this?

Thank's a lot for your answers!!!

I really don't believe its a firmware issue with these lenses. Because this anomaly occurs only on the wider end of the aperture scale, it really seems like it's a physical issue, maybe a lens group or something. If you happen to have a body that exaggerates the lens' misalignment, you could be beyond the AF adjustment window. The 100-300 I wrote about in that thread apparently worked very well with only a minor adjustment for the next owner.

+1, most likely a calibration issue which can be done on the lens (at your cost if it is out of warranty).

We need to be careful with bandying about the word "calibration." There's only so much that can be done to any lens within a reasonable cost. If you can't get it performing using the in body AF adjustment, a camera repair shop won't be able to do anything else either. I was told in no uncertain terms by CRIS that neither they nor Sigma could do ANYTHING with the lens because of its age. No parts, etc were available. About the only thing I think you could possibly do is find someone willing to take apart the lens and adjust the lens elements, if that would really have an effect.

I spent many hours testing, calibrating, re testing, and taking it to 2 different camera repair shops (along with my K3 body). I think I exhausted every option EXCEPT purchasing a new body. I eventually just decided to sell mine at a steep discount and pick up a 2nd gen lens because that was the least expensive option and guaranteed the most reliable outcome.

I'm sorry you are going through this frustration, been there, done that. I love the Sigma 100-300, and it broke my heart to find out the one I had was "defective." But I was also extremely relieved to learn that it was actually a known issue, and that my lens was some quirk of the universe, or that it was something I was doing wrong. It just falls under the "Stuff happens" category.

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Last edited by nomadkng; 06-29-2016 at 08:15 AM.

[afrayssi]

I really don't believe its a firmware issue with these lenses. Because this anomaly occurs only on the wider end of the aperture scale, it really seems like it's a physical issue, maybe a lens group or something. If you happen to have a body that exaggerates the lens' misalignment, you could be beyond the AF adjustment window. The 100-300 I wrote about in that thread apparently worked very well with only a minor adjustment for the next owner.





We need to be careful with bandying about the word "calibration." There's only so much that can be done to any lens within a reasonable cost. If you can't get it performing using the in body AF adjustment, a camera repair shop won't be able to do anything else either. I was told in no uncertain terms by CRIS that neither they nor Sigma could do ANYTHING with the lens because of its age. No parts, etc were available. About the only thing I think you could possibly do is find someone willing to take apart the lens and adjust the lens elements, if that would really have an effect.

I spent many hours testing, calibrating, re testing, and taking it to 2 different camera repair shops (along with my K3 body). I think I exhausted every option EXCEPT purchasing a new body. I eventually just decided to sell mine at a steep discount and pick up a 2nd gen lens because that was the least expensive option and guaranteed the most reliable outcome.

I'm sorry you are going through this frustration, been there, done that. I love the Sigma 100-300, and it broke my heart to find out the one I had was "defective." But I was also extremely relieved to learn that it was actually a known issue, and that my lens was some quirk of the universe, or that it was something I was doing wrong. It just falls under the "Stuff happens" category.

I have the same problem with my istds, k10d and k3ii even with +20
With the k3ii live view, focus is correct... so I thought it could be firmware problem.


Thank's a lot for all your aswers