EX1 and wobbly footage

[Ronnie Martin]

How does the HQ 720p 60 footage compare to 1080i 60 down converted to SD when shooting fast moving objects? I shoot dirt racing at night where the light changes every 50-60 feet and the cars are moving at over 100mph and have been using 1440X1080i shutter at 60. The results have been pretty good except for some artifacts on horizontal lines when down converted then burned to SD DVD. The main issue that I have had is nailing focus. My perch is usually way up on a press box and I am shooting down following the cars around the track. When the light is low the depth of field is shallow. Most of the time focus is set to infinity but infinity is not against the infinity stop on the Fugi lens on the EX. It keeps changing. Is this a camera issue or pilot error on my part? The footage when viewed on my Sony HD monitor is super. It is when the down convert to SD on the timeline the artifacts occur. The Editing platform is Edius 4.61.

Thanks
Ronnie Martin
http://www.dirtracingvideo.com

Ronnie Martin
Kato Video Productions