Track Photo "mistake"?

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This was taken with the 120-300, and helped define back focus issue. I initially kept the shot as proof, but the more I look at it, the more I begin to like it. What say the experts?

WRT back focus, the lens owner says it was user error. As soon as I changed back to the 70-300, had high percentage of keepers.

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This was taken with the 120-300, and helped define back focus issue. I initially kept the shot as proof, but the more I look at it, the more I begin to like it. What say the experts?

WRT back focus, the lens owner says it was user error. As soon as I changed back to the 70-300, had high percentage of keepers.
It sure looks to me like the camera/lens just locked focus on the second runner rather than locked on the first runner with a ton of back-focus or the auto-focus isn't keeping up with the runners coming at you and thus focuses behind the target (usually not the fault of the lens).

But, if the 70-300 works better for you, you might as well just stick with it as long as you have as much light as you do here. The Sigma will shine when the light is low and you really need f/2.8 or when you want to blur the background with a wide aperture. At f/4 and 300mm, it should also be substantially sharper.
 
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Agreed, this probably isn't an example of backfocusing, it is more likely an issue of the wrong person being focused by the camera. Been there/done that.
 

gvk

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Mystic, CT
This was taken with the 120-300, and helped define back focus issue. I initially kept the shot as proof, but the more I look at it, the more I begin to like it. What say the experts?

...
Yes, this looks more like an example of mis-focus rather than back focus.

With regard to the shot, I don't think it works in this case. You would have to blur the foreground runner a bit more, and get a better angle on the trailing runner. I often attempt to use DOF for separating runners; sometimes it works, and somtimes it just looks like you missed focus. It is easier to blur trailing runners since the leader is more obviously the main subject. DOF can sometimes be used to feature one runner in a pack, but generally you have to get close and shoot wide open for it to work. It is hard to do with sprinters since there is not much space separating the runners.
 
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Thank you for the replies

This is that lens that I couldn't get to focus on anything. All the pics went from mildly oof, to way oof. It was incredibly fast to focus, just didn't do a good job of it. WRT the runner in the pic, I had been tracking her all along, if the camera chose the further away runner, then it was way outside the focus box.

My biggest complaint with the 70-300, it just can't focus as fast as I would like. Does a pretty decent job, but I couldn't get a good pic of the youngest, as she outran it's ability to focus.
 
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My biggest complaint with the 70-300, it just can't focus as fast as I would like. Does a pretty decent job, but I couldn't get a good pic of the youngest, as she outran it's ability to focus.
It's a bit hard to say whether not being able to keep up with a fast runner is the fault of the 70-300 or the D50. One of the things that you get in the more expensive Nikon bodies is much faster auto-focus response. I shoot soccer (often with players coming straight at me) and I finally decided I needed something faster than my D70 in order to track subjects running at me with better accuracy. Even after practicing my D70 focus technique and sending body and lens to Nikon for focus calibration adjustment, I still had issues with my D70. When I finally upgraded my camera body, that made a huge difference in my hit rates for focus on subjects moving towards me.
 
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It's a bit hard to say whether not being able to keep up with a fast runner is the fault of the 70-300 or the D50. One of the things that you get in the more expensive Nikon bodies is much faster auto-focus response. I shoot soccer (often with players coming straight at me) and I finally decided I needed something faster than my D70 in order to track subjects running at me with better accuracy. Even after practicing my D70 focus technique and sending body and lens to Nikon for focus calibration adjustment, I still had issues with my D70. When I finally upgraded my camera body, that made a huge difference in my hit rates for focus on subjects moving towards me.
I believe what you say is what I am experiencing the most. When I go out and shoot sports with my Sigma 50-150 I notice that my focus is not exactly on what I want it to be on and I think that has more to do with the D50 than the lens. I am lusting for a D200 to really get the focus faster and more precise, but other things are needed right now. Hopefully I will be able to get the D200 and keep the D50 so I can test the two side by side to see how they both perform in the same conditions.
 
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Is this a full frame shot? Center AF point? AF-c?
Cropped and off the top of my head, not by much
Center AF point AF-C and centered on the closest runner.

It was suggested the runner actually out ran the focus. Bad part about that, the 70-300 can keep up better then that. I might get something slightly oof, but not that far, and most certainly not most of the pics taken.

Responding to another post, I know there are better bodies available, but SWMBO is having a tough time with lenses that have 4 significant digits, LOL I even suggest another camera, game over!

Seriously tho, I'm only making occassional pennies playing with this stuff. If I got serious about it, then maybe, but it would never replace the daytime job, I'm just not good enough!
 
Joined
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I believe what you say is what I am experiencing the most. When I go out and shoot sports with my Sigma 50-150 I notice that my focus is not exactly on what I want it to be on and I think that has more to do with the D50 than the lens. I am lusting for a D200 to really get the focus faster and more precise, but other things are needed right now. Hopefully I will be able to get the D200 and keep the D50 so I can test the two side by side to see how they both perform in the same conditions.
D300 is going to be released in the next, suggest waiting
week
three weeks
two months
six months
18 months
when hell freezes over

LOL
 
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