Keep in mind that video on a DSLR is not like a Video camera - Video cameras shoot at 50fps and some higher end cameras can be changed to 25fps.
In HD on DSLR cameras, the only choice you have is 25fps
This is called film Judder - you can replicate this using actual movie film - its only seen DURING PANNING a camera. DSLR cameras replicate film at 25fps because the "shutter" is the pixels sending information captures at 25fps... Judder occours optically when one frame captures an image, then the second frame captures the movement, and the 3rd captures a still frame and the 4th captures movement. This Movement Im talking about is a frame that is slightly smudged, or blurry and is the result of certain objects moving faster than the given shutter speed. At 25fps, we can notice this movement as it is slow enough for our eyes to see.
This DOUBLE imaging is basically our eyes noticing objects that move across the screen faster than other objects where the blured frame follows a sharp frame and it looks like its juddering behind the object. It doesnt happen all the time, only on certain objects like a striaght vertical line it MIGHT as the image mixes with the objects around it.
In old movies, judder was hidden by the fact that directors would only PAN the camera where there are no vertical objects and always at distances.
Here is a link about the differences and advantages of interlaced video (video cameras) and progressive (dslrs and higher end video cameras) http://www.hometheaterhifi.com/volume_7 ... -2000.html
1) Olympus OM1 [Zuiko Auto-S 50mm f/1.8]
2) Pentax MZ-60 [Sigma 28-90 & 100-300]
3) Canon 7D [EF-S 15-85 & 70-200mm f/4 IS & 50mm f1.4]Leo's Flickr Page