As suggestions, I would say that you are too low for how close you are. It probably would have been fine if you had used a longer lens (more telephoto) and had been further back. It hard to give numbers with the wide variety of digital camera sensor sizes, but for film and a shot like this, I would say at least 50mm. I'd also like to see them looking at your lens rather than off at someone else.
heheh MarkC, I just read your post in another portrait post, and there you also suggested using telephoto lens... well I think that tele lens is useless here... there's a nice background, but the composition might have been better. I see a bit of mess in this photo.. I mean... you look up to see small kids - something's wrong here. Kids are looking somewhere else than straight in your camera BUT the photo is posed - it also gives a bit artificial effect here. What's more... the girl is lost somehow because the boy is much taller than she is, and her white blouse is lost somewhere with the background...
because the background is straight behind the kids. And you would make it slightly (only slightly blurry). And I'm afraid that the viewer might have problems with recognizing that it is a gate. To be honest I like completely blurry background but to achieve it, the bg must be quite far from the subject. On the other hand I like very sharp, recognizable backgrounds like this one. I don't like things in the middle - not really blured and not really sharp.
While here I think that the very sharp gate looks great - it looks very rural and girl's clothes are rather rural as well
You could easily fix that with a narrower aperture. But I don't think you would need to. When the distance between camera and subject increases, so does the DOF. If they had used an 85mm lens, then they would have had to back up to frame the image the same. This would have increased the DOF. They might not have had to even adjust the aperture, since the background is so close to the kids.