Steve Perry
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 p.6 #4 · UPDATE - Nikon D5/D500 Dynamic AF Issue | |
la puffin wrote:
Hi Steve, I'm just trying to make sense of all this, and I really appreciate all of the time you've put in helping others with your posts, videos and the delicious cookies you sent me for my birthday 
Here's something to consider. Could this be a deliberate change of function that is directed at shooting sports? Remember, the D5 was released in time for the Olympics. Shooting sports, you want use the AF point you've chosen because most of the time, one is shooting wide open whether for separation from the background or because of shooting in low light conditions. With a razor thin DoF, accuracy with the AF point is crucial for the difference between a pretty sharp shot and a tack sharp shot. Dynamic AF is a helper to get a close relative until the photog can get the AF point back onto (a contrast) target, and as soon as that happens, the computer in the camera goes back to the primary point. This is what one would want - AF on the chosen point.
A couple of little scenarios:
1) D9 for basketball. Focus on a eye, player moves, AF point goes on a check and can't focus. Nearby point picks up contrast on the side of the nose, shot is made and within the range of DoF. Photog gets the primary AF point back on the eye and continues. Don't you want the AF back on target instead of staying with the helper? I want it to ficus where I'm trying to focus. Using D25, the larger area might catch his hand near his face as he's making a shot and DoF is too short and you get a sharp hand and slightly OOF face.
2) D25 for motosports. Shooting a black car with white number on the side. That's a nice big contrast point, but the photog loses the white number and the primary AF point moves off slightly and loses contrast to focus as all black is in the primary AF point. D9 is too small, but D25 can reach the side of a number and achieve AF. Being the crack shot that I am (ha ha ha), I move the primary AF point to the driver's head in the window. I don't want the camera still using the helper, I want it to go to the primary AF point. Doesn't this make sense? DoF is probably deep enough to cover it, but it's just an example.
Thinking further about the D5 as a sports centric camera, is the issue of lower DR at low ISOs. Shooting sports in daylight with a fast aperture, under exposing isn't really an issue, unless a clown like me has EC set down two stops. What's more likely is over exposing, and I can't remember where I read it, but the D5 has a good degree of headroom here (highlight recovery). Once the photog starts shooting in less light (and with a higher ISO) is where DR is more important and which is where the D5's DR is improved over other cameras.
I could be completely wrong, but I'm tossing out that there is another way at looking at the function of the camera. I'm not being a D5 apologist, I'm not going to dump it if they changed the AF behavior to be more like the D810. I also have too much spare time this morning if I'm thinking about these kind of things. I should go buy some shoes  ...Show more →
Don't get me wrong, I'm open to the idea that Nikon may have just changed the way it works, that's one of the reasons for this thread However, I'm not sure what the point is. The problem is that the camera isn't handing off the AF point so...
In your first example, the camera isn't actually handing off the AF point to another one when the photographer loses the eye. In all of our tests, the camera never shows a switch to another AF point in the array. Instead, it's more likely just using the time set in the Blocked AF Response to before trying to refocus. I'd say in that scenario, you could get the same results with Single Point. In my mind, Dynamic is only useful if it does what you describe and hand-off the AF point to somewhere else in the field when the first one loses the lock. As for precision, that's the reason there are different size Dynamic areas, to keep the AF isolated to the area you want. If you need to be really precise, that's when you use Single Point. Again, maybe Nikon has changed this deliberately, but I still think it may be a glitch that would be very correctable in firmware.
In one of the posts above, Howard mentions how much better the Dynamic is on the D810 - so action shooters (I know he's a wildlife guy too) are seeing the difference. If they did change it, they went the wrong way IMO.
In your second scenario, again, same problem. The camera isn't actually handing off the AF point like it should. Now, if there's no other contrast to lock onto, the camera will pick anything in the array (although, oddly, it still doesn't register this as a different AF point).
My thing is this - if Nikon changed it, what's the point of making Dynamic act like Single Point AF? I can even see them putting in some kind of extended delay so you can get back on target, but that doesn't seem to be the case either. As it sits, we have Single Point AF with what seems like an "Auto AF" area surrounding it, ONLY coming into play if there is absolutely nothing to focus on under the primary point. It's not a tracking mode at all like this.
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no D500 under-the-bus tossin' here! Just trying to figure out why it's doing what it's doing in Dynamic and if it's not working right, just hoping for some firmware