Nikon Soft Focus – Need Help Diagnosing

whiplash23

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My son just started playing soccer and I have tried to take some photos at two of his games. Both times, the images have been very soft. I assume the problem is me, but I wanted to get some advice as I would love to blame this on the lens :)

First, I have a D90 and am using the Nikon 55-200 VR at the games. I set the camera up as follows:
AF-C
Dynamic Focus or 3D Focus
Manual exposure (shot at F7.1 - 1/500s last game, shot at F6.3 – 1/1600s this game, you know just in case it was camera shake last week)
Auto ISO (it stays below 400)
VR = Off

When I use this lens on AF-S, I get acceptably sharp results. It’s nothing like my 50mm 1.8, but I don’t expect it to be. However, as soon as I put it on AF-C everything just gets soft and it is driving me nuts.

I have noticed that higher priced telephoto zoom lens seem to focus faster than the 55-200 (I have tried the 70-300 ED and the 80-200 F2.8). So I am wondering if that is the issue.

So, my questions are:
Do I have my settings screwed up?
Is this an AF-C issue in general?
Is this a “cheap” lens issue?
Or, do I just suck (I assume this is where the smart money is)?


Here is the obligatory crappy snap:
1221164250_oD3DP-X3.jpg
 
why are you not using it in vr mode, that is one of the purposes of a lens of that type?
 
If you look at the grass from that picture you can see where the field of focus starts and ends (theres almost 2 horizontal lines on the ground where the focus shifts from being in focus to being blurry). Anyway, if you look at their feet, it seems like they're right outside (or on the edge) of the field of focus.

My 2 cents:
- Try to get a more accurate point of focus on the children. If you think you can predict where they will be for a shot, you can even use single point AF so you know for sure what AF point is being used (but u gotta make sure that point is always centered on one of the children).
- An easy but kind of half-assed fix would be to go for a smaller aperture so the field of focus is larger.

Also about the VR i dont think it would have mattered if he had it on or off since he was shooting at 1/500 sec or faster. But then again I don't think it hurts to just leave it on either :p
 
If you look at the grass from that picture you can see where the field of focus starts and ends (theres almost 2 horizontal lines on the ground where the focus shifts from being in focus to being blurry). Anyway, if you look at their feet, it seems like they're right outside (or on the edge) of the field of focus.

My 2 cents:
- Try to get a more accurate point of focus on the children. If you think you can predict where they will be for a shot, you can even use single point AF so you know for sure what AF point is being used (but u gotta make sure that point is always centered on one of the children).
- An easy but kind of half-assed fix would be to go for a smaller aperture so the field of focus is larger.

Also about the VR i dont think it would have mattered if he had it on or off since he was shooting at 1/500 sec or faster. But then again I don't think it hurts to just leave it on either :p

I have read that leaving it on when unnecessary drains the camera battery faster.
 
As mentioned above a large part of your issue is related to depth-of field (DOF), which is the near and far range of what will be in reasonably sharp focus, if you.

At 1/1600 VR has virtually no effect so having it off is not an issue.

The plane of focus is always parallel to the image sensor. When multiple subjects are at unequal distances to the image sensor they are in effect on a diagonal and not parallel to the image sensor.

Using AF-C and shooting sports takes practice and a fair amount of skill. Using only 200 mm, I bet you are having to crop photos to get decent image scale, which will magnify any focus issues.

Tip: shoot the action as it is approaching you so faces and expesssions can be seen, not as it is going away from you (backs of heads).
 
Would single focus point be better for this application?
I don't use anything else, and haven't had a focus issue.

Just wondering if that might help the situation.
 
Thanks for the input! I didn't expect DOF to be an issue given the distance that the players are from the camera, but I'll keep that in mind next week and see if I can't get something in the f10 or f11 range.

KmH, you are absolutely correct that I am having to crop the images pretty significantly. I wish I had more lens but that 55-200 is the longest lens in the bag for the time being. I appreciate the tip, but I put the one of the kids' backs up on purpose. I didn't want to post other people's kids to a public forum w/o their permission and that one didn't show the other child's face (and was as out of focus as everything else). You say that sports and AF-C take a lot of practice to get right, what should I be thinking about?
 
You don't want to be using f/10-f/11. f/5.6- f/8 will work fine.

When I shoot outdoor sports I use aperture priority, float the ISO (auto ISO), and keep my eye on the shutter speed in the camera viewfinder. I don't want it go below 1/500.

When using AF-C it's a good idea to move the focus function from the shutter release to the AE-L/AF-L button on the back of the camera. (AF-On mode - see page 200 of your D90 users manual).

If you shoot with your right eye to the viewfinder keep your left eye open to follow the action, because you have to be able to antisipate the action to get nicely focused shots. Antisipating what kids might do is tough because they don't play using conventional soceer strategies, KWIM?

The Multi-CAM 1000 focus module in the D90 only has 1 cross-type focus point, the middle one, and that's the one you want to use because it's the most accurate one of the 11 focus points. You can always crop to your final image composition later (rule of thirds and all that), but as I mentioned cropping in effect magnifies the photo so you have to expect sharpness to suffer to some degree. Your 55-200 mm lens is a consumer grade kit lens, and does a great job for it's price, but it's a consumer grade kit lens.
 

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