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03-23-2013, 03:12 PM   #1
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Tracking-focus question

I am starting to use Back Button Focusing, along with Tracking focus.

Here's the question. If I focus on a moving subject, the little square follows it, like over to one side of the screen, as it moves. But I cannot get the little square to come back to the center of the screen, unless --

1. I take a picture ... then it centers, ready for the next shot

2. I wait a few seconds, and then it centers

Is there some button-press way to tell it to center the focus square, like right away?

P.S. I don't think BBF has anything much to do with this... the little square still stays away from center when you are using the half-press shutter button.

03-23-2013, 06:08 PM   #2
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Try pressing 'OK' - that seems to always recenter the focus area no matter what the mode.
03-23-2013, 07:13 PM   #3
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Thanks Rob! I'm off to the races!

Or, since the track at Del Mar doesn't start up for a few months, I'll go after anything that moves tomorrow.

Today, I took my first BBF picture. A small plane towing a huge ad banner. Holding down the AF/AE-L button, the focus locked on the banner and stayed there, until I took the picture just before it went behind a tree. M/TAv, at f/7.1, 1/1250 sec, Auto-ISO 640... could have used a slower shutter speed, but was hoping a jet would come by, instead of the dead-slow cropduster and banner.

Also thanks with this to Sledger, who told me about Back Button Focus on our K-01 thread on the Xara-Users forum. Xara is a great art program I use to salvage errant photos. Anyway, I'm looking forward to practicing BBF next week -- just got a taste of its promise today, and it should be a real help in future.
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Last edited by jon404; 03-23-2013 at 07:21 PM.
03-24-2013, 07:59 PM   #4
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The cropduster came back today. Here's what I learned. Using back Button focus, with Button Customization > AF/AE-L button > Enable AF2, and AF/MF Settings > Autofocus Method > Tracking, I had trouble with my 55-300mm telephoto. When it worked, holding down the button to keep it tracking, everything was fine. But if I wobbled the lens and the focus square slipped off the plane, it went nuts hunting for a new focus,and I lost the picture. Will not use Tracking in future for telephoto airplane pix!

Now, they must think I want to buy Geico insurance, because that little banner-towing plane came by a second time. And this time, I changed the Autofocus Method from Tracking to Spot. Put the focus square on the plane, pushed the button just long enough to get a focus lock, which the K-01 then held without having to hunt for a new focus inbetween shots. It worked. And here's the kicker -- the K-01's AF made MUCH sharper pictures than I was getting the other day on MF manual focus. For me, it is VERY hard to estimate the distance to a flying plane. At 300mm, there's no room for error. It is closer than infinity, but how much closer? And no time to use the Magnify focus, too easy to lose the plane when you do that on Manual.

There IS a trade-off. When you use BBF, you can't use the AF/AE-L button for an Exposure Lock. On page 88 in the manual, it says that on Custom 1, you can Link AE to the AF Focus Point (2)... with Multi-Segment metering only... but it didn't work. But once I went from Tracking to Spot focus, with Spot Exposure metering, I was OK... for getting that moving subject. Can always go back to Exposure Lock for non-moving images!

Anyway, here's today's BBF picture... you can see, even at 260mm, how small that plane was in the frame. But the K-01 had no trouble picking it up against the clear sky. As an aside, forget about locking onto a gray plane fling in and out of wispy clouds... you have to give the camera some kind of contrast. And -- very important -- the spot focus lock lets you take sharp pictures only as long as the aircraft is roughly on the same focus plane, at roughly the same distance. Sooner than later, you'll have to take another focus lock, as it moves along.

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Last edited by jon404; 03-24-2013 at 08:10 PM.
03-25-2013, 03:11 AM   #5
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I was wrong, it is the green button that recenters the focus dot. If you use the guide screen, it tells you to use the green button.
03-25-2013, 03:25 AM   #6
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Rob22315 -- It is impossible for me to believe that such a distinguished forum member could be wrong about this, particularly as I have been using your excellent advice to use the OK button -- without any problems at all! Works fine! It's... OK! Rob, I'm using my Green button to take a Raw + Jpg combo... so I'm very glad that you were right about this the first time around. That Guide screen is obviously practicing for April 1st.

You know, when you stick a computer in a camera, there are so many wondrous possibilities -- a combinatorial explosion. So many modal situations where something can be this today and that tomorrow. I'm sticking with your OK button to center that Tracking focus point... and thanks again for telling me about it... it really, really helps.
03-25-2013, 04:40 AM   #7
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Here is one technique that I have found useful when you're using BBF with AF-C for objects moving perpendicular to you (not closer or farther from you).

Once you get focus on the moving object (the plane in this case), release the AF button. The depth of field should be enough to keep the object in focus, and you can track it without having to worry about other objects resetting your focus.

This comes in real handy during soccer games.

Last edited by klh; 03-25-2013 at 06:26 AM.
03-25-2013, 05:58 AM   #8
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Alright, well it is one of those two buttons. LoL

I figured out why I was confused. I have the Q and the K-01. On one camera, it's the OK button, on the other, it's the green button.


Last edited by Rob22315; 03-27-2013 at 07:54 AM.
11-20-2013, 02:40 PM   #9
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My K-01 doesn't track focus at all in Tracking Mode; The green square follows the subject but the focus doesn't change at all after the initial acquisition.
11-20-2013, 02:51 PM   #10
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Bossa,

Yeah, the tracking doesn't work at all with purely forward/back movement. I tested this with three lenses. It does work though with lateral movement even if the lateral movement also contains fore/back movement.

Essentially, the subject has to have some left/right movement for the focus to track. Even then, the tracking is not something to write home about.
11-20-2013, 03:25 PM   #11
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Rob22315, jon404, et al..

Rob, you might have been thinking about how the green button is used to center the focus area when the "select focus" mode is used.

Something I use focus tracking for (besides pics of my dogs) is recomposition. If I know the framing needs a focus point that is not in the center I'll put the K-01 in tracking focus mode, focus on what I want as the focal point, and then recompose. Then before I release the shutter I focus again with the correct framing and the focus being where I want it to be by having earlier "tracked" the area.

I do this because the focus tracking area is smaller than the smallest "select" focus area. Whether the actual area used by the camera (between the focus tracking size vs. the select size) is actually different I really haven't confirmed. But if the focus indicator isn't lying, the focus area is significantly smaller.
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