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Old 03-27-2013, 02:05 PM
Jorda75078 Jorda75078 is offline
Larry Jordan
Join Date: Apr 2011
Location: Inverness, FL
Posts: 17
Default Replu re testing 70-180mm

"I was curious about how to interpret the test results. The Quality of focus test shows pretty widely ranging results by focus point. Is this typical? And how to you know which focus points are 1, 3, and 5 (with the good results) and 10 (with the poor results)."

I believe the test you are referencing is the Focus Consistency Test. Those numbers 1 - 10 are just the shot numbers. They are not focus points. I used the same center focus point for each fact, FoCal used the same center point. With this test, you push the start button, and FoCal executes the entire test while you watch. The test just shows you how consistently the camera/lens combination performs autofocus. The Quality of Focus on the left side of the graph indicates how well the camera/lens was focused. It is meant as a relative indication of focus quality.

You may have this test confused with the multi-point sensor test that compares the quality of focus of all autofocus sensors. I have not posted an article about that test yet.

"The chart with different aperture settings seems to confirm the conventional wisdom that f/8-f/9 is the sharpest, but other apertures are usable if DOF is required. Where is the point that you would be reluctant to stop down further?"

I try to stick with the peak quality setting on f/9. However, I do go as high as f/13. I shot flowers today that you will soon see on Facebook. I shot some at f/9, but I also shot about half at f/11 to get some additional DOF. I did use the CamRanger and performed focus stacking for these flower shots to give me a HUGE DOF compared with a single shot. I probably could have stuck with f/9 for all shots, but I wanted some DOF between me and the first focus stack shot in each sequence. CamRanger stacks from where your focal point is backwards away from the camera. (This may be too complex to explain here.)
Larry Jordan
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