Back focus or motion blur.

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Full Frame
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Back focus or motion blur.
10 months ago

Used single point, auto focus. nikon 35mm f/1.8g 1/500 iso 3200.

Inset shows focus point using view NX2.

Also put camera on tripod with same settings and distance at home. Stationary subject, sharp and focused.

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Bruce Granofsky
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

You shot at a shallow depth field. 1.8.

Camera missed the focus on the boy.

Looks like you have both, miss-focus and a bit of motion blur.

Pretty simple me thinks.

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Full Frame
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Re: Back focus or motion blur.
In reply to Bruce Granofsky, 10 months ago

Bruce Granofsky wrote:

You shot at a shallow depth field. 1.8.

Camera missed the focus on the boy.

Looks like you have both, miss-focus and a bit of motion blur.

Pretty simple me thinks.

Inset shows focus point is right on the boy

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dread_tai
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

just missed focus.

with that shallow depth of field, there's no way he AND the wall were going to be in focus. i think the shutter speed would have been adequate to catch him in action based on him, even out of focus.

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Bruce Granofsky
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Re: Back focus or motion blur.
In reply to dread_tai, 10 months ago

dread_tai wrote:

just missed focus.

with that shallow depth of field, there's no way he AND the wall were going to be in focus. i think the shutter speed would have been adequate to catch him in action based on him, even out of focus.

The shutter speed was Not fast enough.

All you have to do is look at the boy in the background, and you can also see that his tiny movement also motion blurred.

As for the 'Focus Point', my 'guess' would be that it registered for a moment on the foreground boy, but then lost it by the time the shutter opened.

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dread_tai
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Re: Back focus or motion blur.
In reply to Bruce Granofsky, 10 months ago

Bruce Granofsky wrote:

dread_tai wrote:

just missed focus.

with that shallow depth of field, there's no way he AND the wall were going to be in focus. i think the shutter speed would have been adequate to catch him in action based on him, even out of focus.

The shutter speed was Not fast enough.

All you have to do is look at the boy in the background, and you can also see that his tiny movement also motion blurred.

As for the 'Focus Point', my 'guess' would be that it registered for a moment on the foreground boy, but then lost it by the time the shutter opened.

no.

that's subjective. i've shot a few events at that shutter speed, and seen others do the same, and when subject correctly focused was more than adequate, especially when no flash allowed.

and of course, the focus point was a momentary thing, i've experience the same whilst shooting my running dog.

we can agree to disagree......

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DesertLefty
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

(1) You need to use AF-C ("continuous servo") to get a shot like that.

You must start off by putting the focus point on the subject, then half press the shutter button to start AF tracking, then press all the way when you want to take the shot.

(2) Even if you start with the center focus point, you want the camera to have the option to switch points as it continuously refocuses. So, you need to set the AF "area" to something other than single. Try 9-point or 21-point. "3D" mode could work for a shot like this with a single player, but can get confused if there are multiple players wearing the same color jersey.

(3) You should also consider setting your shutter mode to CH ("continuous high-speed") in order to capture multiple images in "machine-gun mode".

(4) Nothing wrong with using f/1.8 for this shot, you need it in order to keep the shutter speed high and the ISO low. Gym lighting is almost never ideal.

Practice, practice, practice! Moving subjects (especially sports) are much more challenging than stationary subjects.

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Trazan
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

Full Frame wrote:

Bruce Granofsky wrote:

You shot at a shallow depth field. 1.8.

Camera missed the focus on the boy.

Looks like you have both, miss-focus and a bit of motion blur.

Pretty simple me thinks.

Inset shows focus point is right on the boy

Doesn't mean that focus was aquired at that spot, as it's not a stationary scene or camera. The focus is on the wall behind. When you took the picture the focus point was on the boy, but you either used AF-S, or AF-C didn't have time to refocus.

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j_photo
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

My guess is the camera focused on the wall, prior to the boy running in front of the indicated focus point. But there was insufficient time for refocus before the shot was taken.

If it's back focus, it looks like a pretty extreme case.

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Full Frame
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Re: Back focus or motion blur.
In reply to j_photo, 10 months ago

j_photo wrote:

My guess is the camera focused on the wall, prior to the boy running in front of the indicated focus point. But there was insufficient time for refocus before the shot was taken.

If it's back focus, it looks like a pretty extreme case.

Thanks for all your input

With my D90 always used AF continuous mode at 4.5 fps for sports. Gunning it I knew I was going to get a few shots in focus. But in this situation was sitting 1 foot away from basket. The boy was running toward me. I thought that at that distance would have no problem as the subject should be large enough to acquire focus and was only about 8 feet away. When I shot an air show had no problems using single point as i had a large subject matter. Guess its a learning experience with the D800.

Don't understand why viewnx showed the focus spot that i used, yet the camera used a different point. It would appear that the camera knew that i was panning and switched to predictive/dynamic mode.

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brianric
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Re: Back focus or motion blur.
In reply to Bruce Granofsky, 10 months ago

Bruce Granofsky wrote:

dread_tai wrote:

just missed focus.

with that shallow depth of field, there's no way he AND the wall were going to be in focus. i think the shutter speed would have been adequate to catch him in action based on him, even out of focus.

The shutter speed was Not fast enough.

All you have to do is look at the boy in the background, and you can also see that his tiny movement also motion blurred.

As for the 'Focus Point', my 'guess' would be that it registered for a moment on the foreground boy, but then lost it by the time the shutter opened.

Shutter speed is more than adequate to shoot grammar school basketball.

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brianric
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

Full Frame wrote:

j_photo wrote:

My guess is the camera focused on the wall, prior to the boy running in front of the indicated focus point. But there was insufficient time for refocus before the shot was taken.

If it's back focus, it looks like a pretty extreme case.

Thanks for all your input

With my D90 always used AF continuous mode at 4.5 fps for sports. Gunning it I knew I was going to get a few shots in focus. But in this situation was sitting 1 foot away from basket. The boy was running toward me. I thought that at that distance would have no problem as the subject should be large enough to acquire focus and was only about 8 feet away. When I shot an air show had no problems using single point as i had a large subject matter. Guess its a learning experience with the D800.

Don't understand why viewnx showed the focus spot that i used, yet the camera used a different point. It would appear that the camera knew that i was panning and switched to predictive/dynamic mode.

What mode were you in? The D800 doesn't switch to dynamic mode by itself. I have a feeling you were in AF-S mode.

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Full Frame
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Re: Back focus or motion blur.
In reply to brianric, 10 months ago

brianric wrote:

Full Frame wrote:

j_photo wrote:

My guess is the camera focused on the wall, prior to the boy running in front of the indicated focus point. But there was insufficient time for refocus before the shot was taken.

If it's back focus, it looks like a pretty extreme case.

Thanks for all your input

With my D90 always used AF continuous mode at 4.5 fps for sports. Gunning it I knew I was going to get a few shots in focus. But in this situation was sitting 1 foot away from basket. The boy was running toward me. I thought that at that distance would have no problem as the subject should be large enough to acquire focus and was only about 8 feet away. When I shot an air show had no problems using single point as i had a large subject matter. Guess its a learning experience with the D800.

Don't understand why viewnx showed the focus spot that i used, yet the camera used a different point. It would appear that the camera knew that i was panning and switched to predictive/dynamic mode.

What mode were you in? The D800 doesn't switch to dynamic mode by itself. I have a feeling you were in AF-S mode.

Yes it was in AF-S mode.

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brianric
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

Full Frame wrote:

brianric wrote:

Full Frame wrote:

j_photo wrote:

My guess is the camera focused on the wall, prior to the boy running in front of the indicated focus point. But there was insufficient time for refocus before the shot was taken.

If it's back focus, it looks like a pretty extreme case.

Thanks for all your input

With my D90 always used AF continuous mode at 4.5 fps for sports. Gunning it I knew I was going to get a few shots in focus. But in this situation was sitting 1 foot away from basket. The boy was running toward me. I thought that at that distance would have no problem as the subject should be large enough to acquire focus and was only about 8 feet away. When I shot an air show had no problems using single point as i had a large subject matter. Guess its a learning experience with the D800.

Don't understand why viewnx showed the focus spot that i used, yet the camera used a different point. It would appear that the camera knew that i was panning and switched to predictive/dynamic mode.

What mode were you in? The D800 doesn't switch to dynamic mode by itself. I have a feeling you were in AF-S mode.

Yes it was in AF-S mode.

That's your answer. Put it in AF-C, either 9 point or 21 point dynamic focus. Adjust A3, Focus tracking with lock on as required. Same goes for A1, AF-C priority selection. I have A1 on my D800s and D3S to Release + Focus. The Df only has Release and Focus, not Release + Focus, which is another hit against the camera. I can't offer advice on A1 for the Df because I haven't used it yet at a basketball game. First game for me is January 8.

Opps, you're using D800, set A1 for Release + Focus.

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HobbiesAreFun
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

Full Frame wrote:

j_photo wrote:

My guess is the camera focused on the wall, prior to the boy running in front of the indicated focus point. But there was insufficient time for refocus before the shot was taken.

If it's back focus, it looks like a pretty extreme case.

Thanks for all your input

With my D90 always used AF continuous mode at 4.5 fps for sports. Gunning it I knew I was going to get a few shots in focus. But in this situation was sitting 1 foot away from basket. The boy was running toward me. I thought that at that distance would have no problem as the subject should be large enough to acquire focus and was only about 8 feet away. When I shot an air show had no problems using single point as i had a large subject matter. Guess its a learning experience with the D800.

It is much easier to acquire focus at a distance than at close range. At close range, slight movements to or from the plane of focus will bring something out of focus, as the depth of field is smaller when focusing on something at a closer range (this in particular is exacerbated by the fact that you are using a full frame camera body).

Don't understand why viewnx showed the focus spot that i used, yet the camera used a different point. It would appear that the camera knew that i was panning and switched to predictive/dynamic mode.

It showed which focus point had been used to acquire focus. It does NOT show where focus was acquired. This is a more advanced SLR than your previous D90, which means it requires more manual effort on your part to switch it to the right settings, and know what settings to use or not to use for a given situation. Its potential is greater, but it is more complex.

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Full Frame
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Re: Back focus or motion blur.
In reply to HobbiesAreFun, 10 months ago

HobbiesAreFun wrote:

Full Frame wrote:

j_photo wrote:

My guess is the camera focused on the wall, prior to the boy running in front of the indicated focus point. But there was insufficient time for refocus before the shot was taken.

If it's back focus, it looks like a pretty extreme case.

Thanks for all your input

With my D90 always used AF continuous mode at 4.5 fps for sports. Gunning it I knew I was going to get a few shots in focus. But in this situation was sitting 1 foot away from basket. The boy was running toward me. I thought that at that distance would have no problem as the subject should be large enough to acquire focus and was only about 8 feet away. When I shot an air show had no problems using single point as i had a large subject matter. Guess its a learning experience with the D800.

It is much easier to acquire focus at a distance than at close range. At close range, slight movements to or from the plane of focus will bring something out of focus, as the depth of field is smaller when focusing on something at a closer range (this in particular is exacerbated by the fact that you are using a full frame camera body).

Don't understand why viewnx showed the focus spot that i used, yet the camera used a different point. It would appear that the camera knew that i was panning and switched to predictive/dynamic mode.

It showed which focus point had been used to acquire focus. It does NOT show where focus was acquired. This is a more advanced SLR than your previous D90, which means it requires more manual effort on your part to switch it to the right settings, and know what settings to use or not to use for a given situation. Its potential is greater, but it is more complex.

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Thanks, just thought that it being an advanced camera you could use single point in that situation. Will go back to AF-C at 4fps.

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lickity split
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A great video...
In reply to Full Frame, 10 months ago
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Trazan
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

Full Frame wrote:

HobbiesAreFun wrote:

Full Frame wrote:

j_photo wrote:

My guess is the camera focused on the wall, prior to the boy running in front of the indicated focus point. But there was insufficient time for refocus before the shot was taken.

If it's back focus, it looks like a pretty extreme case.

Thanks for all your input

With my D90 always used AF continuous mode at 4.5 fps for sports. Gunning it I knew I was going to get a few shots in focus. But in this situation was sitting 1 foot away from basket. The boy was running toward me. I thought that at that distance would have no problem as the subject should be large enough to acquire focus and was only about 8 feet away. When I shot an air show had no problems using single point as i had a large subject matter. Guess its a learning experience with the D800.

It is much easier to acquire focus at a distance than at close range. At close range, slight movements to or from the plane of focus will bring something out of focus, as the depth of field is smaller when focusing on something at a closer range (this in particular is exacerbated by the fact that you are using a full frame camera body).

Don't understand why viewnx showed the focus spot that i used, yet the camera used a different point. It would appear that the camera knew that i was panning and switched to predictive/dynamic mode.

It showed which focus point had been used to acquire focus. It does NOT show where focus was acquired. This is a more advanced SLR than your previous D90, which means it requires more manual effort on your part to switch it to the right settings, and know what settings to use or not to use for a given situation. Its potential is greater, but it is more complex.

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http://eswenson.smugmug.com

Thanks, just thought that it being an advanced camera you could use single point in that situation. Will go back to AF-C at 4fps.

You can use single point, if you're sure to keep it on the subject, but you need to use AF-C on a moving target.

I only use the AF-ON button for fucus, like this: http://www.youtube.com/watch?v=WyPv1bLkwqAHah, lickity beat me to it!

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clarnibass
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

Full Frame wrote:
Thanks, just thought that it being an advanced camera you could use single point in that situation.

That might work if you are fully pressing the shutter button and you have Focus Priority set, so it would take the photo the moment it is in focus. The problem is, even in that mode, that it's likely to have a moment (even a fraction of a moment) between getting focus and taking the photo. But in AFS mode, once the camera gets focus it will not change it and follow anything. So you should really use AFC in a sitaution like this and whatever else is basically a matter of preference (single point in AFC can work too, depending on how you do it).

But another thing is that just because the focus point shows to be on the kid doesn't mean that's where the focus is, regardless of mode. You can see that if you try to focus on a completely uniform target (i.e. no contrast at all for AF) then it wouldn't AF. But, if there something contrasty sligthly to the side of the focus point, it will still AF to that cotnrast. The focus point is not limited only to its exact area.

In this case, the contrast between the kid and the wall is much higher than the contrast on the kid. It's very possible that the camera "chose" this contrast to focus on and in this case either the kid or the wall would be in focus and it "chose" the wall.

In this situation where you have a subject contrasty from the background, I look in the viewfinder if focus is on the subject.

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j_photo
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Re: Back focus or motion blur.
In reply to Full Frame, 10 months ago

Full Frame wrote:

Thanks, just thought that it being an advanced camera you could use single point in that situation. Will go back to AF-C at 4fps.

You need to study up on the difference between AF-S and AF-C. Single point area mode is available in both AF-S and AF-C. The difference between the two is what happens to focus when the subject moves.

Once AF-S acquires focus it will not change. It is intended for stationary subjects. AF-C will continuously adjust as the subject under the focus point moves. It is intended for moving subjects.

It looks like your camera focused on the wall behind. Once focus was achieved, that's where it stayed.

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