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09-16-2011, 01:01 PM   #1
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So how do YOU handle focusing on moving objects?

Curious to know how fellow Pentaxians handle focusing on moving objects – specifically, objects/people moving toward you. Continuous/servo AF? Manual focus pre-focused to a zone? “Catch-in” focus?

Tracking horizontally isn’t a problem for me, but admittedly, I’m hit n’ miss with subjects (usually runners and cyclists) moving toward the camera. The work I do in these situations usually requires shallow DOF for subject isolation, so pre-focusing to a zone is tricky, as there’s not much leeway. The ACS on my K20D doesn’t seem to ‘keep up’ with these subjects very well and “catch-in” focus doesn’t work for my purposes. Please share your wisdom.

Also, the one Sigma lens I use with OS, I’ve used both settings #1 and #2 (OS and tracking OS) and notice no difference with forward-moving subjects between the two.

Thanks,

Fuzzy At Times


Last edited by veezchick; 09-16-2011 at 01:03 PM. Reason: typo
09-16-2011, 01:08 PM   #2
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I try to either manual focus to a zone, or even use AF to focus to a nearby object of the same distance.

Unfortunately this doesn't work if my subject doesn't move into the focused zone.
09-16-2011, 01:12 PM   #3
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For moving objects, there are a few tricks. Here we are talking about moving onjects towars yourlsef.

* Use Tv to control the shutter speed. You will need at least 1/30s (walking person) to 1/8,000s (fast approaching vehicle). You may consider also full manual. (In my case, I often use the P mode and set the shutter speed with the dial.)

* Use Hi Continuous shooting.Do make sure that you switched off (kill off) all in-camera post-processing. (PP)

* Then there are two 'schools'
- AF.C (or Continuous/servo AF)
or
- Manual focus pre-focused to a zone.
I prefer to use the latter because I learned to estimate distances: I set the distance on the focus ring and I start shooting before the object move in that location. I found that this technique gives me the better 'keeper rate'.

(EDIT: catch-in-focus may work for runners and cyclists, but definitely not for motorised objects... or birds.)

Hope that the comments will help.

Last edited by hcc; 09-16-2011 at 04:54 PM.
09-16-2011, 02:40 PM   #4
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K-5.

09-16-2011, 04:39 PM   #5
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I wouldn't try AF.C on a K20D. The camera just doesn't do continual focus well. I'll second the idea of pre-focusing. Catch in focus can be helpful but getting to it is not quick and works best for single subjects, not an event where there are multiple subjects.

Those of us of a certain, ah, maturity had to learn to pre-focus on moving objects. In my case, I had a twin lens reflex camera that not only didn't autofocus but displayed a mirror image through the viewfinder that seemed to move opposite from the subjects actual direction of travel. Still, I learned to shoot track meets with the camera.
09-16-2011, 04:45 PM   #6
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Original Poster
QuoteOriginally posted by Ubuntu_user Quote
K-5.
That's just wrong! ;-)
09-16-2011, 05:27 PM   #7
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What I've been trying Lately is using continuous mode (slow, in this case) and Catch In Focus. I'm currently using a manual lens though. That way, I can just hold down the shutter release and turn the focus ring. Even in continuous drive, the camera will not take a photo until it sees focus confirmation. Sometimes it works, sometimes it doesn't but I've never been very good at moving subjects anyway.

09-16-2011, 05:45 PM   #8
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All the usual tricks.

1) On manual-focus cams: prefocus; zone-focus; judge distances; fast shutter and/or strobe; shoot when it looks right.
2) On autofocus cams: Same as (1); burst|continuous spray and pray.
3) On my K20D with manual-focus lenses: Same as (1) and (2); CIF.
4) On all the above: Practice practice practice.

09-17-2011, 04:23 PM   #9
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I am having similar problems with K7 and 55-300 DAL lens combo. My problem subject is a football game with players moving in all directions and at different distances. If by chance the subject is isolated from surrounding movements the focusing seems quite ok but if there is any moving players in the frame everything just stops. The camera can't decide on a focus point. I have removed all in camera processing, AFC AFS, Centre focusing, and selected focusing but the problem is still there. Manual focusing on the 55-300 DAL is difficult on a fast moving subject. I find the focus ring too light and too highly geared. The issues are more pronounced the closer I am to the action. My only solution is to get a bit further back from the subject and crop heavily. I lose some detail but that is not so important from my purposes.

Would another higher quality and no doubt more expensive lens provide any relief? If there are any tips or further suggestions I would grateful.
09-17-2011, 04:40 PM   #10
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I prefer manual focus and burst at 7 fps, depending on lighting and aperture the settings, it can be as easy as focusing where you think/hope the action is going to be and let'er rip!
09-17-2011, 04:55 PM   #11
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QuoteOriginally posted by Bruce Clark Quote
Would another higher quality and no doubt more expensive lens provide any relief? If there are any tips or further suggestions I would grateful.
Fast zooms solve many problems. Money solves many problems. The two are related, eh? There are reasons pro shooters don't use kit zooms. And there are reasons I don't own pro zooms. Money influences everything. Many folks would recommend a Sigma 70-200/2.8; some, a Sigma 120-300/2.8. Those folks have larger budgets than I. That jump at 300mm from f/5.6 to f/2.8 is quite significant, four stops. Boost your ISO by 4 stops and see the action-stopping difference. Like a superfast fifty, a fast long zoom just does stuff that other lenses can't. And hay, it's only money.
09-18-2011, 03:36 AM   #12
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I use AF-C on my K20D with 300mm DA* star.Also spot focussing and prefocus on area close to the action. I used single repeated released shutter presses, rather than Hi cont. Don't know why. Seemed like a good idea at the time. On the 55-300 DA the focusing was to slow. I am quite happy with the results These are saved as low resolution jpegs, but are quite close to each other time related and it does fulfill the original question. Fast movings subjects coming to you

Cheers

Last edited by Basie; 04-12-2015 at 12:56 PM.
09-18-2011, 03:39 AM   #13
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Doesn't always work but I try to anticipate a spot where the moving object is going to come and I focus on something about where I want it to be when I take the shot like a tree or sign or whatever. By the time the moving object gets there I am already focused to something in that area and it just zooms into the frame and I snap.
09-18-2011, 09:15 PM   #14
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I was out practicing with my new cheaply aquired Bushnell 400mm f6.3 (seems to handle CA"s slightly better than the Vivitar TX I dropped in the rocks..) I got a few keepers, this one I quickly PP'd on the K-5 and then resized for posting.
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09-18-2011, 11:03 PM   #15
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A couple of typical shots to illustrate some of my issues with focusing.

First is a fairly long shot possibly 130 metres and fairly isolated subjects. Camera has no problem focusing on this and rapid multiple shots are possible to capture the moment.

Second show a large number of subjects moving in various directions. If far enough away the camera has little trouble selecting focus. This one is about 50 metres away from the camera. In close say less that 20 metres, it simply can't focus at all. There is just too much going on. The nature of the game (Australian Rules Football) means it is quite difficult to pick a spot and wait for the action to move into the zone.

Simple answer is to accept the technical limitations and try to follow the ball and predict where some isolated action is likely to happen. I normally use the K7 on AF.S shooting in AV mode at F8 and select a high enough ISO to get a shutter speed of 1/500 sec or shorter. Often I have to crop heavily.Quality suffers but that is secondary to the action.

Like RioRico I would love a Sigma 120-300/2.8 or similar but budgets don't extend that far.
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