focus point off on sports shots

[RYSCoach]

New to the forum and I shoot a lot of my kid's sports and on occasion, I run into a frustrating issue where the focus on my shots are not where I am aiming.

Case in point:

http://johnellard.smugmug.com/Other/test-shots/IMG0681/980403095_nuLcV-X3.jpg

Canon Rebel set on AV with AF set to manual and the center spot selected, why is the center of the photo out of focus but the top 3rd of the photo (the trees) in focus.

F3.5 1/1600 ISO 200 with a 85mm lens

Compare that to this taken a bit earlier, with the same camera and lens

F6.3 1/1000 ISO200

http://johnellard.smugmug.com/Other/test-shots/IMG0335/980405396_GLxV5-X3.jpg

Here the center of the photo is in focus and the action is captured.

This issue doesn't always happen but if there is something I am missing that may cause this, I'd love to hear what I can do to avoid it.

[rsquared]

The problem is that on the first photo your focus point isn't where you think it is... Take the photo into your favorite image editor and draw diagonal lines, making a big X, and see where that center point is. It looks to be just barely in front of the woman under the pitcher's elbow, so the camera probably grabbed focus on the fence.

The second picture, the X ends up on the belt buckle of the sliding player, so it's right where you wanted it...

[RYSCoach]

The problem is that on the first photo your focus point isn't where you think it is... Take the photo into your favorite image editor and draw diagonal lines, making a big X, and see where that center point is. It looks to be just barely in front of the woman under the pitcher's elbow, so the camera probably grabbed focus on the fence.

The second picture, the X ends up on the belt buckle of the sliding player, so it's right where you wanted it...


I see what you are saying but then why are the trees all along the top 3rd of the photo in better focus than the lady at the dead center of the photo?

It seemed to me at the time that my camera was not working right because it was shot after shot that was like this.

[Svennie]

What I think has happened is this: you had the focus on the head of the pitcher, while he was waiting to pitch. He started to throw the ball: you press the shutter again and the camera refocuses (software detects the center spot is out of focus, because the head is gone) and apparently it focused not on the fence, not on the woman in the tent or the tent itself, but on the tree directly behind the tent. All elements in the center of the image.
So, your camera is fine.

Oops, sorry... Missed that AF was set to manual. In that case, you just missed the focus. Maybe by accident touched the focus ring?

[RYSCoach]

Oops, sorry... Missed that AF was set to manual. In that case, you just missed the focus. Maybe by accident touched the focus ring?

On my camera, there are up to 9 focus points that the auto focus uses. I had it set to the center only but it was still on auto-focus.

In any case, thanks for the thoughts. It was a strage shooting day in that I got some nice shots and then for a while I couldn't get anything in focus, at least what I wanted to be in focus... :)

[RYSCoach]

Here is a similar case.

This time basketball, so indoors and the lighting is low.

I measured out where the center was and added a small white dot. It is right in the body of the player shooting but as you can see he is out of focus and the background is in focus.

50mm F1.8 ISO400 1/125

I can understand why there would be movement blur but I thought auto-focus is supposed to take something in the foreground vs something further back.

The point of a F1.8 lens is to blur the BACKGROUND, right??? :)

Thoughts on how to avoid this going forward?

I could pick a spot and manually focus to it and hope that I get lucky enough times but would rather not...

Do I invest in a 28mm fast lens or do move further back and try my 85mm? This is where focal length gets me confused when it comes to isolating the intended subject and blurring the background.

http://www.johnellardphotography.com/Other/test-shots/IMG23352/980962357_onybc-X3.jpg

[Icebear]

I'm not familiar with your camera's AF modes, but does it have a "dynamic" mode, where once you aquire focus, the camera will track the object if it moves - so long as you keep your finger on the shutter button?

Also, your focus area spot is a bit bigger than the little white dot. It's going to look for the best contrast within it (which might be the fence) and focus on that. If you're trying to focus on that dark (no contrast) uniform, you're asking a lot of your camera.

[ziggy53]

On my camera, there are up to 9 focus points that the auto focus uses. I had it set to the center only but it was still on auto-focus.

In any case, thanks for the thoughts. It was a strage shooting day in that I got some nice shots and then for a while I couldn't get anything in focus, at least what I wanted to be in focus... :)

When you choose a single AF point the other AF points are ignored. Do try to keep this in mind and a focus recompose is generally acceptable in these situations.

You mention that you have a Canon Rebel series camera and they are designed for general purpose photography, not sports. Sports photography are the most demanding of AF systems.

When I switched from a Canon dRebel XT/350D to a 1D MKII body and started using sports lenses my keeper rate nearly tripled. The EF 85mm, f1.8 USM should be able to keep up with most sports situations but the dRebel body will be limiting, especially in indoor and night sports. The EF 50mm, f1.8 is definitely not a sports lens and will not deliver consistent results in that situation. Neither is the EF 50mm, f1.4 USM, for that matter, although focus accuracy in static situations is much better on the f1.4 than on the f1.8. Use your 85mm, f1.8 for best results (with your current lenses).

Even in the 1D/1Ds bodies you will not get a 100% keeper rate, and that includes using the best technique. Accept that some images will be off and compensate by shooting more images.

My own technique, especially for difficult light situations, is to use single-shot AF mode for constantly changing activity, like indoor basketball and volleyball. I half-depress the shutter button to keep the focus close to where it's needed and then fully-depress the shutter when I see the desired shot.

For more predictable activities like outdoor American football in good light I use AI-Servo mode and then tap the shutter button halfway frequently to keep the AF active. Remember that AI-Servo mode needs a little time to "aquire" the motion statistics so you need to be preemptive of when you will actually take the shot. I then take short bursts, usually 3-5 images.

Upgrade your body and improve your technique and you should be able to considerably increase your keeper rate.

[racer]

I see what your problem is (in the last shot), you were using sports/automatic mode (says so in the exif). I am pretty sure that the sports mode automaticly sets AI-servo, so it will continuly refocuse as the subject moves. That can cause problems when the subject is in one spot moving, were the focus will jump back and forth between two areas, in that case, the player and the background.
If you still want to use a auto mode (for the last shot), use Program AE, chose single shot AF, use middle AF point, track the player focus a couple times, wait till he stops to shoot the ball, then focus and hold down the button for a few shot burst. Like was said, that will be near impossible with the 50mm 1.8, because it focuses way to slow, but the 85mm should focus fast enough

[RYSCoach]

When you choose a single AF point the other AF points are ignored. Do try to keep this in mind and a focus recompose is generally acceptable in these situations.

Right and that's why I selected the single AF point. If I had it with say all 9 active, wouldn't I be more likely to get something else as the main point of focus, like a vivid background?


When I switched from a Canon dRebel XT/350D to a 1D MKII body and started using sports lenses my keeper rate nearly tripled. The EF 85mm, f1.8 USM should be able to keep up with most sports situations but the dRebel body will be limiting, especially in indoor and night sports. The EF 50mm, f1.8 is definitely not a sports lens and will not deliver consistent results in that situation. Neither is the EF 50mm, f1.4 USM, for that matter, although focus accuracy in static situations is much better on the f1.4 than on the f1.8. Use your 85mm, f1.8 for best results (with your current lenses).

I was thinking about getting the 7D. Thoughts on that?

I was trying the 50MM f1.8 because I was so close to the floor, liiterally 6 feet off the court that the 85mm gave me no chance at getting the hoop in with the players (with them being under 5 feet tall, no slam dunks...) :)

And if you were to add 1 lens for indoor sports situations, what would it be? Or maybe couple of choice...



For more predictable activities like outdoor American football in good light I use AI-Servo mode and then tap the shutter button halfway frequently to keep the AF active. Remember that AI-Servo mode needs a little time to "aquire" the motion statistics so you need to be preemptive of when you will actually take the shot. I then take short bursts, usually 3-5 images.

Upgrade your body and improve your technique and you should be able to considerably increase your keeper rate.

I played with the Servo mode while doing baseball photos and got frustrated at the delay you mention but but with a better body (one that can do more than the 3 FPS mine does now), I can adjust and start clicking a fraction quicker, knowing I will then get more chances of getting the shot I want.

[ziggy53]

Right and that's why I selected the single AF point. If I had it with say all 9 active, wouldn't I be more likely to get something else as the main point of focus, like a vivid background?
...

Try using multiple AF points. I think you will find that the AF system generally chooses foreground over background. The problem with multiple points is that it takes longer for the AF system to acquire focus, which is why it's not a good choice for sports.

... I was thinking about getting the 7D. Thoughts on that? ...

The Canon 7D AF system works very well for outdoor and good light, not as well for indoor and night sports. The AF system is certainly better than any dRebel, but not as good as that in the 1D/1Ds series. In poorer light the 7D actually slows down, it even says so in the user manual, but the exact reason for the slowdown is not clear.

That doesn't mean that the camera slows to a crawl, but it is a noticeable slowdown.

More importantly, the 7D is not as accurate to focus in indoor and night sports as is the 1D/1Ds series. The 7D would still be a major upgrade over your dRebel.

... I was trying the 50MM f1.8 because I was so close to the floor, liiterally 6 feet off the court that the 85mm gave me no chance at getting the hoop in with the players (with them being under 5 feet tall, no slam dunks...) :)

And if you were to add 1 lens for indoor sports situations, what would it be? Or maybe couple of choice...
...

In basketball, I do think you would appreciate the results from more intimate shots of individual players and the basketball. I can certainly understand your wish to capture more of the interactive moments between the players and the hoop.

Unfortunately Canon has given most attention to the longer lenses and sports:

http://www.usa.canon.com/app/html/EFLenses101/app_sports.html

I do think that the EF-S 17-55mm, f2.8 IS USM should work pretty well on a crop camera, but I have not had occasion to use mine for indoor sports. I do find others saying it works fairly well. It might force you into using very high ISOs in order to maintain an appropriate shutter speed. Do try not to get hit or run over because the build quality of the EF-S 17-55mm probably won't tolerate much abuse.

Occasionally you will find the EF 50mm, f1.4 USM used for indoor sports, although the AF motor is a "micro-USM" and I would not recommend it myself. According to http://www.the-digital-picture.com/Reviews/Canon-EF-85mm-f-1.2-L-II-USM-Lens-Review.aspx, he would use the EF 50mm, f1.2L USM for sports but he would, "plan on a lower hit rate - especially with the tiny depth of field at f/1.2."

I think that your EF 85mm, f1.8 USM should work well if you position yourself for the needed FOV.

The EF 135mm, f2L USM is just splendid for the more intimate views.

... I played with the Servo mode while doing baseball photos and got frustrated at the delay you mention but but with a better body (one that can do more than the 3 FPS mine does now), I can adjust and start clicking a fraction quicker, knowing I will then get more chances of getting the shot I want.

"Responsiveness" is more important than frames-per-second (FPS), although more FPS generally means more responsiveness as well. Responsiveness is things like:

Frame rate
Focus speed
Shutter lag
Viewfinder blackout
Memory card write-out speeds

Experience with the particular camera will tell the best anticipatory lead times but it's just important not to expect instantaneous lead times. I do suggest "one-shot" AF mode with basketball since the action often changes quickly in speed and direction. AI-Servo is a predictive AF and depends on sampling "predictable" speed and direction.

You may not have the budget for 2 cameras but I suggest that for important games, 2 camera bodies is extremely helpful so that you don't have to change out lenses during the game. Renting a body is often a viable option.

[RYSCoach]

Try using multiple AF points. I think you will find that the AF system generally chooses foreground over background. The problem with multiple points is that it takes longer for the AF system to acquire focus, which is why it's not a good choice for sports.

I'll try that again. I had found that when I have more than 1 AF zone on, it would seem to focus on whatever the most obvious item in the frame was, which too often was say the trees or a fence or in the hoops shot the sign in the background. I thought having just the one would be better but it seems like if I miss having that dot on the inteneded subject even by small amount, it is worse than having the 9 points all on.



In basketball, I do think you would appreciate the results from more intimate shots of individual players and the basketball. I can certainly understand your wish to capture more of the interactive moments between the players and the hoop.

That's a good point. At the time it seemed like I was too close with the 85mm but the more of the frame the player takes up, the less chance the AF picking the sign 50 feet behind the player as the focal point... :)

Occasionally you will find the EF 50mm, f1.4 USM used for indoor sports, although the AF motor is a "micro-USM" and I would not recommend it myself. According to http://www.the-digital-picture.com/Reviews/Canon-EF-85mm-f-1.2-L-II-USM-Lens-Review.aspx, he would use the EF 50mm, f1.2L USM for sports but he would, "plan on a lower hit rate - especially with the tiny depth of field at f/1.2."

I think that your EF 85mm, f1.8 USM should work well if you position yourself for the needed FOV.

The EF 135mm, f2L USM is just splendid for the more intimate views.

I don't mind needing several shots to get 1 that is usable. I plan on that now. Even when the focus is spot on, the shot itself may suck.

I am still trying to figure out the "math" behind photography. Even on some of the hoops shots with a F1.8 lens it seemed like there wasn't any good blur. the ratio of distace between me the player and the player and the background wasn't right to get the result I wanted.

"Responsiveness" is more important than frames-per-second (FPS), although more FPS generally means more responsiveness as well.

True. With the baseball shots (very tight shot on the batter and catcher), I found that if I clicked the first shot before the ball got in the frame, by the time the next one fired, the swing was already through the plate. Being able to get an extra shot off inbewteen the 2 I would take would be huge.


You may not have the budget for 2 cameras but I suggest that for important games, 2 camera bodies is extremely helpful so that you don't have to change out lenses during the game. Renting a body is often a viable option.

The answer here is: it depends. I have been laid off from my "real" job for a while. So, dropping thousands of dollars on new equipment is scary. But if I am going to do this more than a hobby, I know I need to make the investment.