1/1000s is not enough???

Sorry for posting on this already debated argument. As far as I know,

using a high shutter speed (1/1000s) would be enough to freeze the

movements of a running person. In case I'm wrong, I can't imagine the

speed I'm supposed to use to shoot really fast subjects in sports.

Last week I obtained blurred subjects (above all the faces) using that

speed and shooting playing children, and the focus was ok (the ground

near the feet was sharp).

Am I doing something wrong?

 

The example: 1/1000 f5.6 70-200f4L@160

 

Thanks!<div></div>

<p>Why don't you post a full frame picture, where we can see where the focus was/is?

 

<p>The speed of the subject is irrelevant; what is important is the speed at which the subject moves thru your viewfinder. That means that a running (10km/h) child at 2m will need a far higher speed than a 200km/h sports car at 100m, even at the same angle of travel.

 

<p>This photo, for example, was taken at 1/2000, and has normal, but not great sharpness. The kid was at 2-3m.

 

<p><a href=http://www.photo.net/photodb/photo?topic_id=1481&msg_id=00DElU&photo_id=3640202&photo_sel_index=0>Skater</a>

That looks more like a DOF issue than shutter speed. The rear shoe is in focus, the one in front is not.

Here is the full frame image. The examples posted in my first message were 100% crops. I don't think it would be a dof issue ... the front shoe is just not really sharp (remember, 100% crop!) while the face is really blurred! Thanks for answering.

I can't say what the problem is but I can tell you in the 1960s- early 1970s I was a darkroom guy with UPI in D.C. Most sports,baseball,football and basketball where the light was enough pictures were ussually shot at 1/500th with outstanding results. Not saying you couldn't get blur but most of the time the results were good.

It seems like you were shooting upwards. In that case, the plane of focus is not parallel to your subject but at an angle, so that at the level of the kid's face, it is closer to you rather than at the face. With f5.6, the DOF is probably not sufficient to also make the face sharp.

Santiago: the picture of the skater is really good. I suppose you used an high speed BW film that allowed you to use 1/2000s while closing enough to get the needed DOF (all the subject is in focus, and it is really close to the camera!). Is this correct?

Perhaps your auto-focus is not locking in on the subject quick enough? Often a motor-drive lens helps.

 

I don't mean to talk big or anything, but I've managed to shoot ice hockey as low as 1/400th before (and at f4.5, incidently), so 1/1000th and f5.6 should be more than enough for kids playing.

Alberto, my impression is that the kid turned its head very quickly (front hair, body attitude). His head is almost certainly between the first and front shoe, and both are sharper than the head.

 

I'll go on a limb, and say that the picture was taken at about 100mm, and 6m of distance. At this aperture, you have a more than a meter total DOF(1.1m).

 

If it were at 70mm, and 4.5m, you'd had 1.4m of DOF. And at 200mm and 12m, it would be 1.2m of DOF.

 

 

With regards to the skater picture, well, that depends on how you considerer tri-x. In this case, it was rated @200, as the developer I used halves its speed, and taken with a medium yellow filter (-1 stop), so effective speed was 100.

 

It was a slight overcast day, with hazy sun; photo was taken at f/2, 1/2000. If you look carefully, you'll see that his back arm, and his front arm, and front of skate are not in focus. DOF was about 50cm. I was aiming at isolating his expression, and if I had a stronger filter i'd taken the photo at f/1.4.

 

Focus was good, as i knew in advance what his path would be, and focused in advance; the slight unsharpness is caused by motion blur.

My guess is that this is a focus issue, that the picture was shot from pretty far away (the appearance of the floor tells me that), and from above (you can see the floor), i.e. that the plane of focus is tilted behind the frame.

 

If you look carefully at the head crop, is it evenly unsharp in all direction. In 1/1000s there's no way the head can move in all directions evenly enough to reach such a result. If that was motion blur you'd have blurriness in only one direction.

I agree with Jean, the foreground deck is the give away along with the movement of the head. If you pan you can get good results without the fast shutter speed, thus larger apertures and not losing your depth of field. As always done in manual,results will vary according to gear.

Thanks for all your useful answers.

 

There's another interesting element: the background wall is noticeably sharper at the top and blurred at the bottom. IMO this means I wasn't aligned with the wall (and with the kid) and that my DOF wasn't enough to compensate. Besides, the kid was moving toward the camera, so he was (quickly) going away from my in-focus area, and I was using a one shot autofocus mode on my 300D. Considering also the Jean's comment, I'm now pretty sure it is a DOF problem.

If you were using a single autofocus mode, then the problem may be more closely linked to the camera focusing and then taking the photo a split second after the child has moved away/out of the point at which the camera initially focused on him, rather than DOF.

 

That is to say sure, a huge DOF might have been able to compensate, but the photo being taken with the child being where the camera originally focused would have been the only sure-fire way to get this in focus. As was mentioned, at that distance f5.6 should have been enough DOF to get the child in focus regardless of your plane of vision. Perhaps a continuous auto-focus mode, manually focusing or predicting the child's movement and focusing on that point would have been a solution?

I'd agree - if someone is running towards you and you are on oneshot focus as they run closer they are no longer in focus. Timing not shutter speed.