[Clem Nichols]

I've recently spent some time taking photos of my grandson's 7th grade basketball games, and have been disappointed with the low-percentage of in-focus shots. My K10D stays in the center focus AF-S mode probably 99% of the time, but this hasn't worked very well because of the difficulty of keeping the single focus area on the intended subject and the fact that the shutter won't open if that area isn't in focus. Switching to center focus AF-C seemed to help some, but certainly not very much. My best results so far have been by pre-focusing on the goal area, turning off the shutter half-press focusing, turning off shake reduction, and snapping the picture when the players are in the right area. In order to prevent motion blurring I've been using ISO 1600 (with Imagenomic's Noise Reduction Pro) and using the FA 50 f/1.4 set at f2.4 which gives me a shutter speed of 1/250 or so. (I purchased a Tamron 70-200 f/2.8 with the idea of using it, but even at 70mm it seems a bit long for my purposes.) Needless to say, this gives me a pretty shallow DOF and therefore an unacceptably high number of out-of-focus shots. What I haven't yet tried, and would like advice on, is using AF-C with the focus spot selector switch set to Auto. My reason for not having done so already is that I can't see how the camera is going to know which of the 10 players (or the spectators on the other side of them) I'm interested in having in focus. Can anyone shed light on the logic that Pentax built into the auto-focus, auto-select program in the K10 that tells it which focus spot to prioritize? Does anyone have personal experience in a similar situation which would be helpful? Any advice appreciated, and thanks in advance.

CN

[rfortson]

Using AF-C with auto selection of the AF point is hit or miss, in my experience. I've had the best luck using it with flying airplanes, which are isolated against a constant background (the sky). When I tried it on runners in a race, it worked okay, but occasionally locked onto a different target than I intended.

School gymnasiums are probably one of the hardest places to shoot, due to the lighting. It sounds like you've tried everything I would have suggested. Maybe you could try some creative panning shots at a lower shutter speed to show motion blur with your grandson mainly in focus?

[Lowell Goudge]

one comment I would like to make is that since AF is based upon contrast, and very fast lenses such as the FA50mm F1.4 can be a little soft wide open, it may be that your auto focus is not as precise with this lens because of the combination of low light and lens performance.

There was a poster who was having problems, he felt with front focus (if I recall correctly) which changed based upon whether he focused with his F1.2 50mm wide open or stopped down. I asked at that time if this was possibly the issue, and the post never returned.

As a simple note, I have photographed a lot of stage performances using an F2.8 70-200 and never felt that the AF performance was at issue. I would shoot between 1/125 and 1/250 at ISO 3200. so 1/2 to 1/4 of your light. But to be fair, a stage performance does not get the same range of focus as a basket ball game.

I also went back and looked at some shots from my son's basketball games shot 5 years ago with my *istD and sigma 70-200 F2.8

The biggest issue I see is definition of the focus point. Many of my shots were out of focus because my son was not on the center spot, but beside it, and the spot focused perfectly where it was pointed

I don't know how letting the spot selection on auto would perform, but it;s worth a try

[Clem Nichols]

Russ & Lowell:

Thanks for your response. Lowell, yours raises another question I have regarding Pentax's AF system. As I understand it, there are basically two types of auto focus, phase detection and contrast detection. Furthermore, it's my understanding that of the two, phase detection is the faster. Nikon &/or Canon, I believe, use phase detection for the most part, but switch over to contrast detection when in live view. Does Pentax use contrast detection only? Is this the reason for their slower than average auto focus? I am one of many, I'm certain, who's anxiously awaiting Pentax's next top-of-line DSLR in the hopes of seeing higher ISO performance, less noise, and better continuous auto-focusing, although I don't ever expect to see Pentax become a favorite among sports photographers.

CN

[Lowell Goudge]

Russ & Lowell:

Thanks for your response. Lowell, yours raises another question I have regarding Pentax's AF system. As I understand it, there are basically two types of auto focus, phase detection and contrast detection. Furthermore, it's my understanding that of the two, phase detection is the faster. Nikon &/or Canon, I believe, use phase detection for the most part, but switch over to contrast detection when in live view. Does Pentax use contrast detection only? Is this the reason for their slower than average auto focus? I am one of many, I'm certain, who's anxiously awaiting Pentax's next top-of-line DSLR in the hopes of seeing higher ISO performance, less noise, and better continuous auto-focusing, although I don't ever expect to see Pentax become a favorite among sports photographers.

CN

the AF system is phase detection, clearly stated in the manual.

this does not eliminate the fact that the AF system still needs a sharp image to focus on, and ultra fast lenses are soft wide open. that was the point i was making. it is also why brightly lit high contrast subjects are easy to focus on and focus fster. it is a characteristic of all AF systems

[Kerrowdown]

I do a lot of indoor sports and gig band photography, you must remember that basketball is a fast sport and the lighting is usually what can only be described as very poor, so your right it aint easy.

I now use manaul focus only, shake reduction on and I'm prefocused on a given area usually in the basket zone, I try to capture the action and not have to worry about the focusing

[monochrome]

My sense is AF Pentax bodies (generally) and K10D in particular have a 2-step focusing routine - 1) approximate the focus, then 2) sharpen. You can hear this as two distinct movements of the screw-drive. It allows a high hit rate and particularly sharp photos when given the time to work, but is a bit slower than other brands' algorithms. The screw drive is probably a bit slower than an HSM motor, as well.

I have shot lacrosse outdoors using AF-C and a 55~300 zoom - I know that is an entirely different set of challenges from indoor basketball - and found AF-C hunted a lot at first.

I ended up setting the focus point below the center point since players' belly buttons move around less than their arms, shoulders and legs; zooming out to capture all of the body and stick (thus the focus point is at about the belt line); decoupling AF from the shutter release (back button AF), multi-segment meter and shooting about 1/500, f/9.6 - f/11, TAv, -1/3EV, with an ISO 800 ceiling. I got shutter release whenever I wanted it and almost everything was in focus (due to expanded depth of field).

Here is a link to the resposnes to MY question about how to set up the K10D for Lacrosse - Lowell made some helpful suggestions on that thread, too, IIRC.

https://www.pentaxforums.com/forums/pentax-dslr-discussion/37177-help-sports-...otography.html

I found it helpful to my psyche to remember that just over a decade ago photographers were taking your shots using film, pre-set ISO and older lens designs (well, not older than the FA50/1.4). A decade before that thet were using MF lenses.

We think WE have it hard!!

[dosdan]

Based on my recent experience with flying birds shots, I'd suggest another strategy. ISO1600-3200 (Don't know if the K10 has 3200 - I use a K20 - noise is less objectionable than OOF), F8-F13 for DOF. MF, panning, no SR. You'll have a slower shutter speed but much greater DOF, so you rely on panning to get a decent shot.

Dan.

[Gooneybird]

Although I do very little sports photography, I do frequently shoot moving objects like birds and animals. My success using any form of AutoFocus with my K10D leaves a lot to be desired, less than 50% were focused where I intended. So recently I bought the Katz Eye split prism screen and have been doing everything by manual focus since. My success rate at shots focused where I wanted them has increased significantly, and I'm still learning. Actually, the hardest part is trying to predict where the subject will be, after I've focused at what I hope will be its location. Practice and practice seems to help.

Olin

[Clem Nichols]

Monochrome:

Thanks for the link. It contains very valuable information. Based on Lowell's advice, I think next time out I'll try the Tamron 70-200 f2.8 which seems to be much sharper wide open than the 50mm f/1.4 is even at f/2.8. I'm also going to experiment with AF-C using the auto-select mode instead of center focus. One of the posters in your previous thread reported that he got many more in-focus shots with that method. One definite conclusion I've reached is that shooting at ISO 1600 with the K10D is not a "no-no" as long as you have some type of noise reduction program in post-processing. Another definite conclusion is that one of the great benefits of digital photography is to be able to experiment almost endlessly without the cost of film and developing and without having to wait two or three days to see your results. I have to believe that this has probably made all of us better photographers.

CN

[kenyee]

Clem: I'd also suggest trying to decouple AF and the shutter release. There are a bunch of tips here in case you're curious:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/48938-tips-af-usage.html

[monochrome]

Monochrome:

Thanks for the link. It contains very valuable information. . . .

To paraphrase the movie, just passing it forward. Again.

[Clem Nichols]

Clem: I'd also suggest trying to decouple AF and the shutter release. There are a bunch of tips here in case you're curious:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/48938-tips-af-usage.html

Kenyee:

That, indeed, is a good suggestion, and one which I'm already utilizing. Thanks.

CN

[kenyee]

That, indeed, is a good suggestion, and one which I'm already utilizing.

Sorry, Clem. Missed that you were doing that already :-P

not mine, but some basketball shots with a sigma 70-200..there's a link to flickr for the exif data:
Celtics vs. Rockets @ The Garden 01/07/09