<p>Jeff, in response to your request for samples I uploaded 4 pics to a gallery in one of my websites. I also gave the question of movement a good deal more thought. So here are my pics and comments:</p>
<p>Firstly in this type of dancing, generally there are groups of six who stand in two lines of three. The first couple then cross to the other side, do some fancy twirls and then move to the end of the group then stop. The next couple repeat the process. I will be shot if any Scottish Country Dancer sees this description but it is just to give photographers an understanding that the frame will contain people standing still, and people moving around in circles or swapping positions. Every movement is with a skip step.<br>
<br /> <a href="http://www.whitepixels.ca/p457276687/h4f4e0d61#h4f4e0d61">http://www.whitepixels.ca/p457276687/h4f4e0d61#h4f4e0d61</a><br>
<br /> This should bring up Pic1 taken years ago with a D300, 34mm, 1/125 sec, F6.7.<br /> What is evident is that sharpness of the dancers depends upon how much they move across the frame during the exposure time. OK, we all know this but seldom think about it.<br /> The girl in the middle with the brown skirt is not in focus, but she is moving fast across the frame (see her hair). Her partner, the boy in the blue kilt has just about finished moving as far back as he can, so his relative motion with respect to the camera is essentially zero, so he is sharp. His kilt shows residual swing.<br /> The same thing applies to the couple immediately right. The girl in black tights has come towards the camera so relative motion is zero and she is quite sharp, but her partner in the white top is really active.<br /> The older lady on the right is moving much slower but also is moving directly towards the camera, so is sharp.</p>
<p>Click on the next thumbnail and Pic2 shows three women dancing together. This is D800, 24mm, 1/100 sec, F4.<br /> The woman on the left is clearly moving as her dress has billowed out but the hands and faces are quite sharp as the movement is along the lens axis at this point. One can also see two men in kilts with their right feet sharp and almost touching the ground as they skip.</p>
<p>The next image Pic3 shows a girl in red and a woman in dark blue. The dark blue dress flounces out as the woman curves in to meet her partner. In the middle ground, there is a woman in light blue who is sharp despite her launching herself into motion. She is in focus because her movement across the frame is still quite small given the midfield distance.</p>
<p>Pic4 shows a pretty woman in dark blue who is really moving fast (see the lean as she dances in a circle), but the relative motion towards the camera is still quite small so she is sharp. The man in black is moving across the frame, his kilt really flying out, but he is quite blurred.</p>
<p>So what does this mean to the OP? Shots should ideally be made at the peak of a movement, just before a change of direction since at this time movement of the body is relatively slow.<br /> In reality in the heat of the moment this is a lot to ask, so just fire away!</p>
<p>But we have to ask ourselves what type of pic is wanted. In my opinion a shot of ballet dancers destined for a fine art print might demand cross frame sharpness everywhere.</p>
<p>However with just about any other type of dance, especially if you want to show people having fun, you need to show movement of clothing and limbs to avoid a totally sterile image. Hence my selection of shutter speed but YMMV.</p>