AF points and sports photography

First of all I apologise for the long and I hope not too confused post.

 

I have posted an image taken of a rugby game I followed recently. I was using

a Canon 30D EF100-400mm f/4.5-5.6L IS USM at 1/1000Sec, F5.6 focal length

400.0 mm (AI Servo AF). The central character in the picture is out of focus

while one of the support players in the black and blue jersey appears to be in

focus. There were a number of pictures with this problem

 

From the various threads concerning AF points, sports photography and the use

of Al Servo on this forum I have believe my problem is as follows. (1) AF

points should be set to centre because if this is not done the incorrect

character could be focused on by the camera. Am I correct? Further, will the

fact that the camera is being used in portrait (as opposed to landscape) mode

(incorrect word used here) impact how the AF point should operate? I suspect

not but confirmation of this point would be appreciated.

 

(2) Al Servo only works adequately if the subjects are moving head on to the

camera with no frequent change of direction such as in a field hockey game

played on water. As such this feature is probably of no use for this sport but

probably fine for rugby. The same holds for the image stabiliser. Would I be

correct here?

 

Many thanks<div></div>

Use of the central focus point allows control of the camera's often rather stupid decision making. Portrait orientation will sometimes create hunting but should not be a real problem.

 

I would use AI Servo, but I have switched focus control to the * button to make it possible for me to control when the camera looks for focus. Use of IS in sports photography is sometimes useful, but a good monopod or tripod with a good ball head would be better in my opinion.

Well, AI Servo is useful for all moving subjects. The more erratic they are, the harder it is for the Servo to retain focus, that is true - but work it will and with modern EOS bodies, work quite well.

 

And IS- in mode 2 - comes handy in reducing lens shake. Of course, as you are shooting at 1/1000, the effect of shake is going to be quite low anyway, but it helps nonetheless.

 

I have an article on Autofocusing that you may find useful:

http://www.photosafariindia.com/articles/tech1-focus.html

 

Cheers,

Vandit

Sometimes you need to have all the AF points active in servo mode. They will hand off focus

from one to another and try to track a moving object. Other times (such as with a mass of

people) it's better to pick one point and use that. Perhaps you need practice panning in IS

mode 2 to get better at keeping the AF point centered on the player.

 

When panning and using IS mode 2 the results can be excellent. Even with a lowly 10D.<div></div>

Here's another one, in case you like Corvettes.

 

The TDI in the above photograph was going at least 70 MPH, and the vette had just applied

the brakes off the straightaway. It was still traveling in excess of 200 MPH.

Many thanks to you all for your advice. It is appreciated. Vandit, your tutorial was most useful.

 

grant

Been doing rodeo photography for a number of years with some footbal and basketball thrown in. I use a 20D with a 70-200 f2.8 non-IS lens. I had similar problems mostly when allowing the camera to choose the focus point. Pretty muched solved the problem by using the center point (the most sensitive one on the camera) and religiously keeping that point planted on what I considered to be the primary point of interest. To help your camera out (and I do this too), you can stop down to increase your depth of field, so that if you miss a bit, your depth of field "saves" you. I always shoot at 1/800 sec or faster unless I'm trying to show movement with a background blur. In good sunlight you can very easily do this at ISO 400, and often at ISO 200. Also, the speed and accuracy of AF is affected by how much light is getting to the AF sensor. If you can afford a faster lens, such as a 70-200 f2.8 or f4, it will serve you better for what you are shooting just because more light is getting to the AF sensor. Good luck.