Chienworks is absolutely right, as usual. If you are intending to print this image you may also find it helps the quality to go to Project Properties to set the Field Order to Progressive and the De-Interlace Mode to Interpolate --- but for goodness sake don't forget to switch them back immediately afterwards otherwise it will be a potential disaster to the project.

Richard

Let me point out something that drove me nuts once. You must be on the timeline, not the trimmer to "snapshot".