High action footage strange choppy sillouetting

[natelaverty]

HI, here I am shooting fast action snowboarding and am experiencing strange sillouetting around the riders bodies when they are coming into frame. It is clear once they are in the centre of the frame but not as they enter frame for the first 2 seconds or so. I should mention, Im seeing this problem during playback on the LCD, the viewfinder, and when i plug in directly from camera to HD tv with the component cables...not just in final cut
I am using a manual focus, shooting 720p/30pn, 1/250 shutter, 4.0 aperature, 30 fps.

here is two still frames, one as the rider is coming into frame and you can see the sillouettes and one as they are in the centre and you can see its much more clear.
Can anyone help?
thanks

[David Jimerson]

Looks like normal motion blur to me, even though you have a pretty fast shutter.

In the first one, the camera is obviously stationary. The boarder is probably moving pretty fast, and even though you have a fast shutter, he's probably still moving fast enough to cause a blur.

In the second pic, you're moving the camera -- the background is blurred -- so you're following the boarder. Relative to the camera, he's not moving as quickly, so there's much less of a chance for blur.

[natelaverty]

you know what that would make a lot of sense I only just started to notice this issue when i began shooting with the camera in a static position on a dolly track. the dolly would be moving but the camera sitting still would make the motion much faster. The strange thing is I just never experienced this with the DVX or shooting 16 mm

[natelaverty]

Can you tell me...are there certain DO's and DONT'S when setting your shutter speed to match your iris? I'm wondering if cranking my shutter up to 500 or 1000 wil fix this? But is there somewhere I need to be setting my iris to match ok?

[David Jimerson]

That fast of a shutter will require quite a bit of light. But you may find you don't like the resultant motion -- not because of the light requirement, but because it'll look very staccato and stuttery.

[seunosewa]

That's just motion blur. It's a good thing.
(You're shooting a video, not a series of images, right?)