# D7k tracking objects at 700mph

Started May 28, 2012 | Discussions thread
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Re: D7k tracking objects at 700mph

Kerry Pierce wrote:

ott77n wrote:

spectator distance from the flight path. As previously stated, all 3 photos in the OP, are moving more laterally to the camera than not, especially the 3rd shot.

I have already explained that photos 2 and 3 are actually frames 2 and 5 in the sequence spanning 0.9 seconds.

That doesn't mean nor change anything. The plane is still moving more laterally to the camera than not, during the photo sequence that you took.

Really? Lets see.
Here is the first frame, unprocessed other then resized:

Note two things: 1 - at 200mm we are looking at 8 degrees, so what you see left-to-right is roughly 6 degrees. Note the position of the boat. 2 - note the time: this frame has 100 millisecond offset.

Here is the second (which is equivalent to the photo 2), un-processed other than like 1

Note the same two things: time offset is 200 msecs, and look at where the boat is.

So, I figure my angular speed was roughly 4 degrees / 100msecs, which translates to some 40deg/second - between first and second frame. And I was already panning slower than the plane was moving.

As you pointed out, the angular speed is going to get seriously higher in the subsequent 800 msecs, so tell me why am I wrong assuming I am looking more than 45 degrees to the left.

Since I am almost certainly right, you couldn't be. I mean in your assertion, let me quote, "The plane is still moving more laterally to the camera than not".

Also, if you want some visual clues, look at the person with a white lens in the middle of 5-th second on that video. See how far "left" is his lens pointing? And that is somewhere like half way thru the one-second-long sequence.

But, even the first 2 shots have little deflection off of 90 degrees.

Yes, a little. Like 60 degrees.
And forget the Super Hornet, this is an illustration of what the BA#5 was after.
Interestingly, on that video he did it, alas "late" in the 7-th second.

I do know what I'm talking about. The video demonstrates that fact nicely. The camera was much farther away from the flight path, than your cropped and edited photos show, which makes it even easier on both the AF and on panning skills. Seems likely that the flight path was far enough away from both of you, that the AF was locked on infinity during the entire run.

How could the AF have been "locked" when it was in 3-D tracking mode?

It could have been locked, had I set the focus to manual and set the lens at infinity. I didn't.

heh, that means that there was nothing for the AF to do, at all.

It doesn't work that way.

But of course, you already know that. You said before you knew how it worked, no? So what are you trying to say here, really?

Next time, lock your 70-200 at 70mm or use a 50mm lens.

How about: the first time you see something like on that video - you do it.

Then come back and share more of your airshow wisdom.

You've demonstrated that you're a rude, ungrateful person,

Ouch. If I have hurt your feelings, I sincerely apologize. But it was you, who had nothing to say other than putdown what I wrote in your first post in this thread.

so you'll join the others in the Ignore listing.

Please don't Ignore-list me, because I don't know what am I going to do, if you will

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