I have had better success with the D850 using 25 point DAF than any DAF mode with the D500 when photographing BIF. I would not expect that the 153 point autofocus system on a DX camera is going to be exactly the same as on a FX camera considering the great deal of difference in the field of view between the two.
On the flip side, I get better results with Group AF on the D500 than I have thus far with the D850. Both cameras though are a big improvement over the D750 camera in terms of autofocus performance, as one would expect. It would be interesting to compare the autofocus performance of the D850 to that of the D5 but for my part it would not be enough of a difference for me to buy a D5 with its weight and bulk and ridiculous price.
I don't disagree with those who don't find D72 and D153 to perform useful additional function; for general photography of people I prefer D9 and find that it does give a significant improvement in hit rate when using e.g. 105/1.4 wide open to make full body shots walking people. The additional points give just enough leeway to compensate for the bobbing up and down of the head during walking and my imperfect pointing of the selected point on the eye, and give close to 100% hit rate. This I cannot achieve with single point. On a longer lens I would need a bit more wiggle room and so perhaps D25 would be appropriate but in practice I tend to prefer D9 with those as well as D25 tends to give the camera too much choice of focus point, the shirt can catch onto the dynamic area and then the face is no longer in focus. D9 seems a sweet spot for steady walking or running people. I also find the area covered to be small enough that I can leave D9 on for general photography without losing too much precision and control.
I photographed figure skating this past weekend and followed Nikon's guideline closely (but not exactly). I used D25 when the (solo) skater was close and pressed the lens button to go to Group Area for a distant skater. This worked very well in general using a 200mm lens. I tried setting the blocked shot delay to 3 as instructed in Nikon's guide but felt the responsiveness of the AF was too slow so I went with setting 2 and this was just perfect for me. I don't find the longer delays are helpful to me and I prefer the speed of response at 2. I tried D9 and felt that I wasn't able to keep that small area on the subject's face so I went with the D25 as instructed in Nikon's guide. The thing that is nice about D25 is that while I point the primary point on the face, the skater's foot or arm can pass the line of sight, and the dynamic area might react to that temporarily but returns the face in focus quickly afterwards (often it doesn't even leave the face), whereas with the old dynamic it could stick to the limb that passes the line of sight and not return to the face after the limb has passed the line of sight. I could never figure out what the old dynamic (e.g. in D7100 or D810) would do until seeing Steve's comparisons and comments and now I understand it better, but knowing how it works doesn't make it useful to me. The old dynamic is simply not precise enough for me to use at the apertures which I want to shoot at.
For ice dance I used initially a 70-200mm at f/4, 1/1600s and auto area AF and this worked perfectly but I was at ISO 5000 and wanted to reduce the ISO for crisper images so I ended up using 1/800s, f/2.8 and ISO 1600, with VR SPORT. Auto area AF is not precise enough at f/2.8 so I switched to group area and that was just perfect. I moved the group area to the intended position and waited the skater to be face towards me and then took shots. Group area seems to be the fastest and most sensitive AF area mode for fast moving action subjects. Dynamic can "take its time" at times and single point may require too much wiggling of the point around.
At no point did I find that I'm running out of options to get shots in focus as I wanted them.
ilkka_nissila wrote:
I don't find the longer delays are helpful to me and I prefer the speed of response at 2. I tried D9 and felt that I wasn't able to keep that small area on the subject's face so I went with the D25 as instructed in Nikon's guide. The thing that is nice about D25 is that while I point the primary point on the face, the skater's foot or arm can pass the line of sight, and the dynamic area might react to that temporarily but returns the face in focus quickly afterwards (often it doesn't even leave the face), whereas with the old dynamic it could stick to the limb that passes the line of sight and not return to the face after the limb has passed the line of sight. ...Show more →
I have three presets for the AF Block Response and Subject Motion. My main sexting I've labelled "Accel" and I have blocked shot set to 1 and motion to erratic. It will jump to a passing object like an arm, but in my real life field sports usage, that object passes quickly and it will refocus on the target really quickly, which is what I want. Also, the target usually moves a bit (football players head), so I'm always looking to keep on my target. D9 gives me a little more wiggle room, as this hypersensitivity is darn fast. I think this would drive some people with a different shooting style nuts. But with long glass and f/2.8, focusing on something other than the target will make the eyes "not razor sharp". That's never a good thing.
In the above link Nikon Professional Services explain how dynamic mode is suppose to work in regards to the outer focus points. It's actually suppose to work the exact same way as it did with previous models. Mine doesn't. Just as yours doesn't. And I don't think anyone's does but I would love it if it did as I would send my camera in to be fixed. The simple test of this isn't to go try to track something moving. Just stand outside, focus on something, then move slightly off the subject but with the outer focusing points chosen still clearly on the subject. The outer points chosen never lock in. The theory that maybe the outer points only lock in if the center point can not focus is incorrect. Nikon says "The camera focuses on the subject in the selected focus point when autofocus is initiated, but if the subject later leaves the selected point for brief periods, the camera will focus based on information from surrounding points"
In the above link Nikon Professional Services explain how dynamic mode is suppose to work in regards to the outer focus points. It's actually suppose to work the exact same way as it did with previous models. Mine doesn't. Just as yours doesn't. And I don't think anyone's does but I would love it if it did as I would send my camera in to be fixed. The simple test is stand outside, focus on something, then move slightly off the subject but with the outer focusing points chosen still clearly on the subject. The outer points chosen never lock on like according to Minkon they are suppose to. The theory that maybe the outer points only lock in if the center point can not focus is incorrect. Nikon says "The camera focuses on the subject in the selected focus point when autofocus is initiated, but if the subject later leaves the selected point for brief periods, the camera will focus based on information from surrounding points"
In the above link Nikon Professional Services explain how dynamic mode is suppose to work in regards to the outer focus points. It's actually suppose to work the exact same way as it did with previous models. Mine doesn't. Just as yours doesn't. And I don't think anyone's does but I would love it if it did as I would send my camera in to be fixed. The simple test is stand outside, focus on something, then move slightly off the subject but with the outer focusing points chosen still clearly on the subject. The outer points chosen never lock on like according to Minkon they are suppose to. The theory that maybe the outer points only lock in if the center point can not focus is incorrect. Nikon says "The camera focuses on the subject in the selected focus point when autofocus is initiated, but if the subject later leaves the selected point for brief periods, the camera will focus based on information from surrounding points"...Show more →
I don't know what used to be as I moved from a D300s which did not have dynamic to a D500. The manual and the link you just posted both say.
"The focus point is selected manually. The camera focuses on the subject in the selected focus point when autofocus is initiated, but if the subject later leaves the selected point for brief periods, the camera will focus based on information from surrounding points" (in the size you selected).
When my subject moves out from the selected focus point I use the small window of time to move the joystick placing the focus selector over the subject. I've never understood how people use back button focus and do this. I use 1/2 press and full press of the shutter release. I have set the delay till refocus to long which makes this easier.
The behaviour seem to match the text though this may not be what previous models did. I suspect you would like the camera to continue to track the subject the way 3D dose and that would make it a lot easier.
