FCP 10.6.8 to FCP X

I am still using FCP 10.6.8 on my older Mac but trying the 30 day demo of FCP X on my iMac 27". My problem is as follows:

When I capture HDV video from my Sony HDV1080i deck into my older Mac using FCP 10.6.8 and then export the footage to an HD QT composite the aspect ratio is 1920x1080. When I transfer this same composite to my iMac using FCP X it still retains the same aspect ratio 1920x 1080. This is good.

However, when I capture video from the same deck into FCP X on my iMac I get 1440x1080. I am unable to export the footage to a QT 1920x1080 format.

Your guidance would be most appreciated.

Thank you.