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7iii front focus conclusion.

Started Apr 25, 2018 | Discussions thread
OP ATLshooter Regular Member • Posts: 395
Re: the obvious question

tko wrote:

How can a mostly digital focusing system fail due to a defect? I mean, pixels are gathered from the sensor, the processor does a lot of calculations and adjust the focus motors until the selected area is sharp, nothing mechanical except the motors and they're part of a closed loop system.

What tolerances are off? How can you have a "subtle" failure? Not having read the 300 some posts, could this be due to focus shift in the lens when it gets stopped down? I mean, ones and zeroes can't be defective, so what was the mechanical culprit?

Or is it a closed loop system? Maybe the processor sometimes only does a one step correction based on calculations . . .

I don’t have an answer for you. I can tell you it most certainly isn’t focus shift because it happened wide open also.

The failure was obvious and repeatable. On both cameras. Both cameras consistently chose the area just in front of where you wanted to focus. Every time. I even did it on video so you could see the results live.

The 7riii that I have now focuses literally dead on the area you put the box around. The 7iii would focus a full 1-1.5 inches in front of the area I chose to be in focus.

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