Need Help with Nikon D3 Focusing Issue

[ray_k]

<p>I have had my Nikon D3 for several years now and primarily shoot MMA and boxing. My primary lens is the 24-70mm f/2.8. The typical setup is manual, 640 to 800ths of a second @ f/2.8, ISO 1000 to 2000.<br>

<br /> For live fights, I go for center-mass of the fighter to make most of the target.<br>

<br /> Recently, I’ve been having a lot of problems with capturing images of fighters (while fighting) in focus. The usual problem is focus elsewhere behind or next to the fighter instead of the fighter themselves. I’ve run though the different focus options such as dynamic area 9/21/51 AF points and AF point selection of 11 and 51. The body is setup for AF-ON on the AF-ON button as well as the shutter. I also mix between dynamic and single AF and spot, matrix, and center-weighted metering. I have also tried focus tracking lock from off through 5 (longest).<br>

<br /> This does not appear to be a back focus issue as the lens lines-up with testing on well-lit subjects.<br /> The body has been reset to factory defaults several times; the issue persists.<br>

<br /> Despite numerous combinations, I seem to catch focus on the fighters surroundings instead of the fighter. When on the fighter however, the image is tack-sharp.<br>

<br /> I am looking for advice on what may be the issue. At this point, it could either be me or the camera settings.<br>

It seems like the camera will focus where it thinks it should focus vs. where I am telling it to.<br>

Any help?</p>

[SCL]

<p>You've turned over too many decisions for the camera to make and it is making choices it was programmed to consider, which is different from the choices your brain makes. I think if you use single point focusing you will achieve better results. This is because often the algorithm for point selection is at least partially controlled by contrast differentiation or edge finding, so with too many focus points the camera seeks the ones which more strongly exhibit differentiation of contrast. Of course, given the focal length of the lens you're using and your distance from the fighters, you might do pretty well with manual focus too.</p>

[ray_k]

<p>When the fighters are closer to me, the issue appears to be less of a problem. It manifests mainly when they are farther, mostly at the far end of the focal length.<br>

I do use single point, center mass of the fighter. The focus however is elsewhere when reviewing the photo. The lighting is decent so contrast is there. Often times, the focus will catch the black chain link fence to the left or right of the fighter (not where the focus point is) instead of the body (where the focus point is).</p>

[elliot1]

<p>I would set A4 to off and use one AF point from the center 3 columns only. If this does not resolve your issue, you may want to have your gear checked.</p>

[mike_halliwell]

<p>+1 Elliot.</p>

<p>Unless I'm missing something, you tell it to do single-point AF and choose the centre point ONLY....the camera MUST do as you say. It could be way out <em><strong>if</strong></em> it looses the fighter but NOT prefer the chain-link fence next door....that's not right!</p>

[ray_k]

<p>I can't really use the center points as there's always distance between the fighters. It would certainly catch focus on the background. I tend to lean towards the left or the right, center mass on the fighter facing me.<br>

Does that make sense? Center point would only work if the subject(s) is in the center, right?</p>

[elliot1]

<p>You best chance for accurate focusing during sports shooting such as MMA/Boxing is to use one of the center points. When I shoot MMA, I always use ONE AF point. When the fighters are close together, I use one from the three center columns which are cross type and give you the fastest, most accurate AF. When they separate slightly, choose one of the outer AF points from the center 3 columns and zoom back a bit, keeping the selected AF point on the one of the fighters while keeping both in the frame. I usually keep it on the rear fighter because he is facing you while the back of the other fighter is facing you (unless they are side-by-side). If they separate more, you have two options depending on the size of the prints you will be making. You can zoom out more and still use the center AF points or choose ONE of the outer AF points and place it on one of the fighters and zoom appropriately to keep both in the frame. Depending on lighting, you may need to select the dynamic AF mode. I would not select more than 9 AF points and would only use this mode when the single AF point from outside the center 3 columns will not achieve proper AF - it is a choice of last resort.</p>

<p> </p>