'ken burns' poor quality interlacing jagged

Question

This post is to document issues with 'Ken Burns' rendering in Final Cut Express 4 and some workarounds and possible bugs in software I found.
Similar posts about this issue:
https://discussions.apple.com/message/5207261#5207261
When I import images into final cut express and  apply keyfram effects with panning and zooming a.ka. the 'Ken Burns Effect' I find that image quality is very poor. This occurs in most BUT NOT ALL images in viewer and canvas windows as well as rendered footage.  The video issues are severe interlacing artifacts (horizontal blurry lines) as well as motion jitter along edges.
Many other users on the web suggested the following, which did not work for me:
-Avoid using JPEG files because their compression introduces artifacts which causes problems for Final Cut
I have found both JPEG and TIFFs have trouble with Ken Burns, although I do have certain TIFFs that seem to work.
-Using different software to render ken burns panning.
This seems silly to me.  I find that the integration of  pan,zoom necessary for fine tuning during editing.  This would be extremely time consuming to separately generate each pan/zoom clip and import. I have heard that some software has high-end smoothing, but I am satisfied with the images that do pan and zoom correctly in Final cut.
-Adjusting Field Dominance in the clip properties to none
this was already set on my clips
-Adjust render settings.
I saw a 1001 rendering 'recipes' offered up to fix image pan/zoom issues. None worked
Things I discovered
Ken burns effect looked great when the image was in a transition, but bad when it was not.  For example: Imagine a 5 second cross dissolve between regular video and ken burns motion image.  When image becomes clearly visible in the latter 2.5 seconds of the transition it looks excellent while panning/zooming. When the transition finishes there is a sudden change to poor quality in the pan/zoom.
-The render bar on top of the timeline is dark-green for good-looking images, which according to the final cut manual, means 'no render necessary'
-There was nothing special about these render-not-necessary images that I could find in resolution, settings, etc.
-Good looking images were jpegs, gifs, and tiffs
I tried converting other images and reimporting, no luck
-I can make the ken burns look good for all images by playing the movie in the canvas window and setting it 99% zoom.
Any zoom level other than 100% looks good.
-This seems like a bug to me.
Eventually I just used a screen recording application called screenflow to capture my video playing in canvas window at 99% in real time.
This worked.
Hopefully someone can explain why rendered images never look good and what format works to get the dark green line and avoid rendering all together and these problems.
I don't mind converting file formats beforehand as long as they work well

Answer 1

The render bar on top of the timeline is dark-green for good-looking images, which according to the final cut manual, means 'no render necessary'
This is misleading. It simply means rendering is not necessary for playback. It does NOT mean that the material does not need to be rendered.
100% zoom level is as close to how your video actually looks that a computer monitor can display.
You never said what format you're working in.
You always have to render still images. You're making video, and they're not video.