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p.1 #1 · p.1 #1 · important info about 7D mk II Outer Focus Point Behavior | |
[B]******** IMPORTANT FYI ********* (copied from other post)
This is a GREAT and CRUCIAL piece of information about the 7D ii AF!!!![/B]
From review by Bryan Carnathan
http://www.the-digital-picture.com/Reviews/Canon-EOS-7D-Mark-II.aspx
Originally Posted by Methodical & MagicMikey View Post on POTN
This part of the review caught my attention. I wander if this could be causing some of the AF issues (note: read the entire passage and not just the red portion).
(QUOTING His REVIEW)
An apparently undocumented attribute of the outer AF points (at least in single AF point mode) is that they all can use contrast information under the next AF point toward the center, causing the adjacent AF point to functionally appear as a focus assist-like point. When contrast becomes weak (or even non-existent) on a selected outer AF point and the next point down/up (for top/bottom AF points) or left/right (for right/left AF points) has good contrast, the 7D II will auto focus using the position of that particular assist point. Here is a pair of examples:
Canon EOS 7D Mark II Outer AF Point Attribute
No Contrast | Low Contrast
I created a white canvas in Photoshop and then created two vertical bars spaced to fall under the rightmost AF point and the next point to the left. The camera is unable to focus on the white canvas (no contrast available), but can easily lock focus onto the black bars. I then reduced the opacity of the right bar until the stronger-contrasting bar under the adjacent focus point took over the camera's attention. The 7D II was tripod-mounted and positioned at an angle to the display to better discern the camera's selected point of focus. Shown in the examples is a screen capture from DPP showing the selected AF point and the area where the LCD display's pixels are most in-focus. The bar under the right-most AF point is still visible in the "Low Contrast" example, but the camera focuses similarly on the strongly contrasting bar to the left.
Corner AF points (including the corner points in the slightly enlarged center section of AF points) utilize contrast information under the two adjacent points.
Whether the outer AF points are simply larger than the point indicator or the adjacent AF point is actually being used, I cannot say. Whether this feature is beneficial or problematic is dependent on the situation you are shooting in. It was somewhat problematic in the horse example I've been showing as the bouncing ears and mane did get the 7D II's attention sometimes. The 5D Mark III's AF system does not exhibit this behavior, but the 5D III's outer AF points are farther from the borders than even some of the 7D II's next-to-outer AF points...
(END QUOTE From Review)
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MY Comment:
I didn't see the image link for the example you created in PS. I am curious whether DPP indicated the outer or the assist point as the active focus point? My guess is the outer point is indicated as active which would drive most crazy. (this is my segway to the following...)
Lastly, WHERE in the menus does Canon provide the ability to turn off this automatic behavior of Use-AF-assist-point-with-outer-or-top-focus-points? This option MUST BE PROVIDED. The photographer must know that he is not getting focus where he intended!!!
Happy Shooting,
Guy
( gschlact )
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