patriot
Offline
Upload & Sell: Off
|
 p.9 #14 · Your 1D Mark III after the fix | |
lamonica66, Which AF point did you use? Do you use DPP? Did you have AF expansion off or on? Was the rest of the sequence in focus?
Here's a possibility, and please understand I am just a hobbiest, so my skills are fairly basic. And I don't shoot much action.
So, with that caveat, here's what could possibly have happened. Could the AF point you used be on the dark area over her ear? Maybe the cam could not focus on that spot? DPP is the only way I know to see where the actual focus point was.
I've seen a few like this one testing AF on my IDMkIII ... I use ACR. Took me a while to figure out what I think was the cause. First, I was using the camera display to see where the focus point was. I know, but I did say I am a hobbiest with beginner skills. So I loaded up DPP, and with that I could explain all but a few from several series of these: focus point had drifted off the target. User error. That would not explain yours, however. But I had a few left like yours to try and figure out ... where the focus point was too far away from the target to be simple drift.
After some time, I realized that the AF point, while basically where I wanted it to be, was on an area that was too smooth to focus on. Then I remembered reading about the AF on this cam, and that the actual AF points were smaller than the box on the screen would make you think. My settings were expansion off. Then looking at what the cam did focus on, I noticed that it was the sharpest contrast in the frame, which may not necessarily be close to the target area. For example, several of these of my dog running .... focus box was on a smooth area of fur that was in shadow ... no detail. The sharpest contrast in the frame, and where the cam focused, was the blades of grass in front of the dog. My son riding his bike towards me, focus box on a smooth blue area of his helmut, camera focused on the sharply defined numbers on his Patriots jersey. My wife on her bike, focus box completely in a smooth area on her forehead, area cam focus on was a crack in a large boulder off to the side and slightly behind her. Her shirt was white, low contrast.
On your shot, if indeed the AF on really on the smooth hair in shadow, the cam may have picked the crack in the sidewalk as the area of sharpest contrast. If so, why it jumped there on that frame could be your AF settings, or just something in the firmware logic that caused the cam to see that as the sharpest contrast in the fraction of a second it had to make that decision.
|
