300mm is the most commonly available maximum focal length. Here is a display of subject height at different locations on the soccer field at Sunnybank Saints Soccer Club, Sunnybank, Queensland. The size of the field is 100m x 66m (to convert approx. to yards, multiply by 1.1 i.e. approx. 110yds x 72yds). The subject is a 9 y.o. 1.36m (4' 6") boy. I shoot a lot of kids' soccer. U9 is the first year the kids use a full-sized field.

The shooting location is mid-field on the side, about 1m back from the sideline. Only the last two (closest) distances have been adjusted to include this extra metre.

Camera is Pentax K20D (14.6MP - 4672 pixels x 3104 pixels - APS-C format) and the lens is the Pentax-DA 55-300/F4-F5.8.

Shown on each photo is:

• The position on the field
• The subject distance
• The focal length
• The percentage of the subject's height, from the bottom of the feet to the top of the head, compared to the total frame height of 3104 pixels.

Some of the shots weren't level, so some rotation (up to 2%) was performed. This reduces the frame height slightly so I've adjusted the percentage a little in these cases.




Position A - Near Corner Kick



Position B - Centre of the Goal



Position C- Far Corner Kick



Position D - Far Sideline



Position E - Centre



In the shots above with a 3000mm FL, the subject has not been able to completely fill the frame height, although an adult subject would have done this in the last shot.

In the next shot, it is possible to use less than the max. FL on the zoom.

Position F - Halfway Between the Centre and the Near Sideline



I then asked the subject to come closer until, at the min. FL of 55mm, he almost filled the frame height.

Position G - Minimum Distance for Full-Height Framing with 55mm FL



These shots show that, even at 300mm FL, solo or small group soccer shots of most field positions will require a fair amount of cropping. The situation would be worse if you can't get that close to the middle of the sideline to shoot. It will also depend on your framing preference, tight or loose, and how much grass & sky you like to include in frame.

I know of a person who uses a 400mm/F2.8 lens on a FF camera to shoot individual sports players. When you consider that 300mm FL on APS-C is equiv. to 450mm FL on a FF, it explains why this FF shooter with this monster lens only sticks to shooting from the ends, rather than from the sides - a player is getting a bit too small from many positions on the field to look good in a blow-up shot. Of course, shooting from an end near the centre means that you've only effectively covering less than half of the action on the field, but it does give the advantage of having the player coming towards the general direction of the camera in your shot.

Dan.

[Monkey Mash Button]

That is tidy and very informative. As a dSLR noob with two young kids, this is good to know. Thanks!

[RonHendriks1966]

That is a good thing. For soccer a 300mm isn't to much.

[dosdan]

For completeness, here's a method based on player height and Angle-of-View (AOV) to determine a subject's distance.

I'll use the shot at Position A. If you copy this image into the clipboard (Alt-Printscreen in Windows) and then then paste it into a graphics program and then check the height of player (I used the cropping rectangle in XnView - Ctrl-Shift-V pastes from the Windows clipboard) you will see that the 1.36m player is 329px high in a frame of 665px height. So the player is 49.5% of frame height. The reciprocal of this multiplied by the player height is the approx. frame height i.e. 2.02 * 1.36m = 2.75m.

Using the AOV calculator here, set to either the Pentax K-7 or K20D sensor (same physical sensor size as the sensor in the K-5 used here), with a FL of 300mm, I inputted a few distances until I got one that gave me a frame height ("Vertical coverage") of 2.75m = 52.8m distance. This is within 5.6% of the of the distance I believed was 50m.

Using the shot at Position C, the approx. frame height is 665px / 204px * 1.36m = 4.43m. At 300mm FL, the vert. coverage is 4.43m at a distance of 85.2m, which is within 3% of the distance I believed to be 83m.

Dan.

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Last edited by dosdan; 12-20-2011 at 07:45 PM.