On Sun, 4 Sep 2016 19:57:43 -0700, Savageduck
wrote:
On 2016-09-05 02:01:38 +0000, Eric Stevens said:
On Fri, 5 Aug 2016 16:35:52 -0700, Savageduck
wrote:
For most purposes I'm a convert to 'back button' focussing, although I
must admit I have never tried it on birds.
"back button" is useful for many subjects, but doesn't do you much good
when shooting a burst while using AF tracking and AF-C for moving
subjects such as those pesky birds in flight.
I've carried your comment in the back of my mind ever since you made
it. So, last Saturday I went round to the local skateboard park to try
it out on the kids flying over the jumps. There were not many doing
that on Saturday morning and the place was cluttered with 2 year olds
being taught by their father .... ! Nevertheless I got a sequence of
one ten year old jumping one of the ramps. On Sunday I went back and
got a few more. You can find the results on
https://www.dropbox.com/sh/a7upuq2tf...0t7CvJbIa?dl=0
The first 7 shots (Saturday) were with D750 and Tamron 24-70. The last
two are D750 with Nikon 70-200.
Nice capture of the sequence and the individual shots.
All shots used AF-C (continuous) with 21 point selected for focus.
Vibration reduction was on although it turned out that it might have
been an improvement to have it off. The shutter was set to high-speed
continuous (6.5 fps). Camera settings we
1. AE-L/AF-L button set to operate (programmed) to AF-ON.
2. AF-C priority set to release priority.
Any reason you didn't use D3-Tracking, or whatever it is called in the D750?
I could have used 3D tracking but I was keeping things simple.
Afterall, this was a trial. I might try #D tracking next week end.
I tracked the subject with my thumb on the AE-L/AF-L button (on the
back of the camera) and started shooting when I thought it was time to
go. The first 7 shots are typical of the results with the 14-70.
It was interesting with the 70-200. The kids were following an
entirely different circuit and were making the jump in the opposite
direction from the day before (that kid facing the camera in mid air
in the second to last shot was actually traveling backwards in mid
spin). First they approached me at speed, made a dive to the left down
a ramp, zoomed across a stretch of concrete and then shot up the next
ramp as photographed. The focus mechanism really worked hard for these
shots and it did work too.
For that type of movement and direction change I would have used AF-C
51 point 3D-Tracking with my D300S.
...but you are using a D750, and I could be totally wrong.
It seemed to work fairly well as it was.
A couple of times I was a bit slow turning on the autofocus and got
there first with the shutter button. I was intrigued to notice that it
was only on the third shot that the images were pulled into focus. No
doubt some of the delay was due to the time required to focus the
70-200.
That is a reason I would leave it to the camera and use AF-C + "Focus
Priority" + 3D-Tracking. Than might slow the frame rate a tad, but that
has been inconsequential for me. I have found that if I use "Release
Priority" I can have a higher percentage of OoF rejects, particularly
with aircraft.
I am now entirely happy at the thought of using back-button focusing
when "using AF tracking and AF-C for moving subjects such as those
pesky birds in flight". Mind you, that's with the D750. I have no idea
of how well it would have worked with my D300.
If it works for you, OK. I have not adopted the back-button focusing
method, other than some experimenting. Perhaps if I use it with a
different camera to the D300S.
I'm sold on it. You should try and get hold of the Rockynook book
http://tinyurl.com/hrfqdsd Highly recommended.
--
Regards,
Eric Stevens