Dale Buhanan

Lives in United States Eagle Mountain, United States
Works as a Electronics Engineer - Semiconductor Technology
Joined on Jul 12, 2007
About me:

Cameras: 7D, 10D, 20D, 40D, 2-50D's, 70D, 2-Pro1's, A95, G5, G6, G9, G15, SD500, Oly-8080wz, SX230HS, SX30, SX40, SX50, G1X-II, G3 X

Canon Lenses: 2-18-135 STM, 35/f2, 2-50/1.4, 50/2.5 macro, 50/1.8 MK1, 60mm macro, 100mm macro, 2-15-85, 17-40L, 2-17-85, 20-35L, 24-105L, 24-70L f2.8, 28-80L, 24-85, 28-105, 28-135, 2-Tamron 28-75.

Process through DPP3&4, PS Elements 7 with Noise Ninja, Many Topaz and PTLens plugins and Portrait Pro 15.


Total: 1, showing: 1 – 1

I became convinced that it was more than a "one look, one movement, open loop" design during the discussion we had some time ago on DPR. I do agree with your observations here, since I duplicated them also. It is clear to me that there is closed loop behavior, although I don't see it as a completely closed loop design in the classical sense.

It is more like a hybrid closed loop approach, or what I would calll a 'piece-wise linear' closed loop, so that oscillation about the focus point cannot occur. ie., the loop doesn't remain closed during the focus process, it is briefly interupted (opened) for evalutation at the end of each movement. That prevents oscillation, and is the best compromise between speed and accuracy.

Excellent work, WilbaW. Good rational thinking, which has furthered all of our understandings on the AF mystery. I am better off with better understanding as a result of your work and my discussions with you. Thanks! -Dale

Link | Posted on Oct 18, 2011 at 17:29 UTC as 12th comment | 1 reply
Total: 1, showing: 1 – 1