Steve Perry Offline Upload & Sell: Off
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Here's an example I'd like to share involving a very simple action scenario.
In this set of images, I was using the D5 (set to 5FPS to keep the number of frames reasonable) with d153. My daughter was running towards the camera and as she did, I placed the center (primary) AF point on her and focused. As she ran, I tracked for a short bit (there are about 10 shots prior to the set below) to make sure the camera did indeed have a lock.
As she ran towards the camera, I reframed so the primary AF point was no longer on her BUT she was still WELL within the d153 area's coverage. As you can see, after a quick delay (as determined by the Focus tracking with lock-on > blocked AF response setting) the camera switched to the background (1frame - 1/5th of a second is all). At no time did the camera hand-off the AF point so it could continue to track my daughter as we would expect.
Any earlier version of Dynamic AF (like on a D810, D7200, D4s, etc), would NOT have released the lock on the primary target in favor of the background. Instead, it would have handed off AF to one of the points covering my daughter and stayed there through the duration. As you can see from the photos, the camera never uses any AF point except the primary.
Additionally, it's also interesting that the Blocked AF response kicked in. That shouldn't happen unless the subject has completely left the field or the camera thought it completely lost the lock.
A scenario where someone is running towards the camera is exactly the type of thing Dynamic should be able to handle, but yet in test after test it gives up the main target for the background - IF the background is a good AF target. A blank background (sky, wall etc) and the camera will stay on target - although I think it’s only grabbing the best area of contrast.
In my opinion, this is acting a lot like Single Point AF surrounded by an AF Auto mode that only kicks in if there is nothing to focus on under the primary AF point. I'm not sure if this is by design or accident, but as you can see from the images, it's a step back either way. The D810 would never let go like that.
Here are a series of six shots as she's running towards the camera and I'm getting ready to pull the primary AF point off of her
Here the main AF point is on her, tracking as expected.
Starting to move off
Off target, but the Blocked AF Response delay is in play so focus stays on target
AF delay is over and instead of handing off the target, you can see it continues to use the center AF point and goes for the background
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