Sigma 10mm Fisheye needed -10 AF adj on K3II

Qwntm · 10-17-2015, 07:25 PM

Wow, first lens I have had to actually adjust the AF adjustment for. It was really bad. -10 and now it seems to focus. I have not tried it at infinity though. On my K5IIs it's fine with no adjustment. I wonder if Sigma has a new Firmware for it to work with the K3II? It's a lens from 2012. Anyone else had any issues with older Sigmas on the K3II?

Adam · 10-17-2015, 07:27 PM

If it focuses fine at -10 I wouldn't worry too much about it- after all, the DOF is huge!

Qwntm · 10-17-2015, 07:50 PM

Originally posted by Adam

If it focuses fine at -10 I wouldn't worry too much about it- after all, the DOF is huge!

Good point. I need to test it some more but it seems ok. Even with that huge DOF, it was OFF big time. That was what was so scary.

I still find it hard to really believe. That a lens could be 100% on a K5IIs and -10 on another body. And the K3II has been 100% zero adj. on all my other lenses. Weird.

**UncleVanya** · 10-17-2015, 09:00 PM

Imagine this. Let's say your body has a mount manufacturing tolerance of +/- .05 mm and the lens is similar tolerance. If you get a body that is +.05 and a lens that is -.05 they work great together. Later with camera "b" you notice the lens focus is off because SURPRISE that mount is a -.05 itself. Now without a +.10 adjustment the lens is out of tolerance.

Edgar_in_Indy · 10-18-2015, 05:18 AM

I wish Pentax would increase the range of available adjustment, as well as making the increments more numerous/precise. Maybe something like an extra 50% in either direction, and providing 20 steps in each direction instead of 10.

Calibration was very different between my old K-x and my current K-30, so UncleVanya is right about bodies varying. The lenses seem to take all the blame though for some reason.

10-17-2015, 07:25 PM	#1
Qwntm Veteran Member Join Date: Jul 2011 Location: Eastern Oregon Posts: 856	Sigma 10mm Fisheye needed -10 AF adj on K3II Wow, first lens I have had to actually adjust the AF adjustment for. It was really bad. -10 and now it seems to focus. I have not tried it at infinity though. On my K5IIs it's fine with no adjustment. I wonder if Sigma has a new Firmware for it to work with the K3II? It's a lens from 2012. Anyone else had any issues with older Sigmas on the K3II?

10-17-2015, 07:27 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	If it focuses fine at -10 I wouldn't worry too much about it- after all, the DOF is huge! Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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10-17-2015, 07:50 PM	#3
Qwntm Veteran Member Join Date: Jul 2011 Location: Eastern Oregon Posts: 856 Original Poster	Originally posted by Adam If it focuses fine at -10 I wouldn't worry too much about it- after all, the DOF is huge! Good point. I need to test it some more but it seems ok. Even with that huge DOF, it was OFF big time. That was what was so scary. I still find it hard to really believe. That a lens could be 100% on a K5IIs and -10 on another body. And the K3II has been 100% zero adj. on all my other lenses. Weird.

10-17-2015, 09:00 PM	#4
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,401	Imagine this. Let's say your body has a mount manufacturing tolerance of +/- .05 mm and the lens is similar tolerance. If you get a body that is +.05 and a lens that is -.05 they work great together. Later with camera "b" you notice the lens focus is off because SURPRISE that mount is a -.05 itself. Now without a +.10 adjustment the lens is out of tolerance.

10-18-2015, 05:18 AM	#5
Edgar_in_Indy Veteran Member Join Date: May 2010 Location: Indiana, USA Photos: Gallery Posts: 2,685	I wish Pentax would increase the range of available adjustment, as well as making the increments more numerous/precise. Maybe something like an extra 50% in either direction, and providing 20 steps in each direction instead of 10. Calibration was very different between my old K-x and my current K-30, so UncleVanya is right about bodies varying. The lenses seem to take all the blame though for some reason.