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07-17-2010, 02:15 PM   #1
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AF-C with the K-7

As is said often the AF system of the K-7 is not yet there in terms of other systems. I'm not using it very often but I tryed it again last sunday at an atletic event in Eindhoven in the netherlands. There was the high jump, at the Eindhoven Atletiek, with the German competitor Meike Kroger (or Meike Kroeger).

I set the camera to the center focuspoint (wich I probably could have better used on Auto selected) so I mist a few shots where Meike was not in the center of the frame. Shot in RAW and developed in ACR, just took of some of the frame on left/right hand to make it square, so nothing changed from top to bottom, sharpend it.

Shot at contiues Hi shooting with the button prest down. So frames missing is from the time the camera takes to get the AF locked. Sometimes as said delaid because nothing was in the middle of the frame to focus on.














[IMG]tp://i28.tinypic.com/osydt2.jpg[/IMG]


A place to discuss the AF-C system of the Pentax K-7

07-17-2010, 03:41 PM   #2
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I see a sequence of perfectly focused photos of a young woman doing high jump. Looks good to me.

Are you sure you were in AF-C? Continuous mode does not require a lock to allow exposure. Or maybe I mis-read your post. If these were done in AF-S, I would say "most impressive". If done in AF-C, I would expect that there were probably a bunch of fuzzy ones in between the good ones. Since Pentax lack a predictive algorithm, focus tracking is usually a bit hit or miss.


Steve
07-17-2010, 04:01 PM   #3
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QuoteOriginally posted by stevebrot Quote
I see a sequence of perfectly focused photos of a young woman doing high jump. Looks good to me.

Are you sure you were in AF-C? Continuous mode does not require a lock to allow exposure. Or maybe I mis-read your post. If these were done in AF-S, I would say "most impressive". If done in AF-C, I would expect that there were probably a bunch of fuzzy ones in between the good ones. Since Pentax lack a predictive algorithm, focus tracking is usually a bit hit or miss.


Steve
Well English is not my first language. With the lock I mean that the system actually takes the picture. It's in AF-c and these are all the pictures. So I left nothing out of the serie.

Last edited by RonHendriks1966; 07-17-2010 at 04:25 PM.
07-17-2010, 04:12 PM   #4
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QuoteOriginally posted by RonHendriks1966 Quote
Well English is not my first languish. With the lock I mean that the system actually takes the picture. It's in AF-c and these are all the pictures. So I left nothing out of the serie.
Well! It seems to work pretty well, I'd say. I don't have a K-7, but if my K10D did this well, I would be thrilled. When I shoot sports/action I usually have to go to manual focus.

Oh of curiosity, what lens was being used for these shots? There is nothing in the Exif.


Steve

(English is my only language...I can only guess how bad I would be if I had ever learned anything else...)

07-17-2010, 04:25 PM   #5
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I used the DA*50-135mm at 50mm, I didn't zoom during this shoot, maybe I shoot have but I forgot. The K-7 was set to iso800 and 1/800st (+0,7EV) and DR-on.
07-17-2010, 06:31 PM   #6
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An excellent series and a nice testament to the Pentax we already have, not the one so many are holding their breath for. Well done.

BTW, at first I thought this was a gag post because when the picture came up, at first glance the statue in front of the man in the blue shirt looked like a live, naked old man.
07-17-2010, 08:17 PM   #7
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Yes, a very nice set of pictures. Most of them look great.
07-18-2010, 05:34 PM - 1 Like   #8
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They are at f13, everything in the frame is in focus.. Try again at f2.8.

08-13-2010, 06:15 PM   #9
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Well spotted, Arpe.

BTW, your BNZ shirt looks pregnant.
08-13-2010, 06:32 PM   #10
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That shirt is def pregnant.

I was going to say the same thing, there's a big depth of field there anyway. It looks fine, but it's not a huge test of AF-C - it's a pretty slow moving target, contrast-y, very bright light...
08-14-2010, 09:59 AM   #11
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Whatever the AFC does, you've taken a very nice series here Ron.
I'm impressed.

- Bert
08-14-2010, 03:30 PM   #12
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Would AFc tracking (at least on the Kx, there's some sort of mention of tracking a subject) be better with all 11 AF points?

i've had some success with my Kx tracking my daughter's basketball and softball games, but i use single center point.

would there be any benefit by using all 11 points?
08-14-2010, 03:34 PM   #13
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QuoteOriginally posted by opiedog Quote
Would AFc tracking (at least on the Kx, there's some sort of mention of tracking a subject) be better with all 11 AF points?

i've had some success with my Kx tracking my daughter's basketball and softball games, but i use single center point.

would there be any benefit by using all 11 points?
With your K-x you can also choose 5 AF-points (an option that is not on the K-7). It's only useful if you cannot keep your object in the center of your image. The K-x has a somewhat slower AF-system, from the K20D I guess, so it could be a little more difficult.

If you like it would be nice to see these pictures. You may put them in this tread if you want.
10-10-2010, 03:45 PM   #14
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Oh man,,,I did not even notice the DOF....I was to busy looking at the high jumper...hehehe
10-10-2010, 04:43 PM   #15
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she is nicely sharp, but your camera is almost perpendicular to her track, and i never had any clue why people have fast lens using them on f13... try av and f/4 at iso200 to test. and choose your position more in her line of running. if she is about 5m away from you, with your settings, depth of field is more than 6m, not a real challenge even for manual focus...
but i must admit that i never tried something similar, just my opinion when reading your post...
good luck
janko
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