Final Cut Pro images show sudden black level pop during zoom

Brian Galford wrote:

I apologize. When I rendered out a short section of video there was no anomaly. It was only on playback in the timeline. Why only there I don't know. But at least its not a problem ultimately.

Whenever I run into a playback problem when playing from the time line, I render the problem section to see if the issue is still there after rendering. You do that by highlighting the clip(s) involved and pressing CONTROL-R. So far the results have always shown that everything plays fine after the render.

Render files are only needed to confirm proper playback of a complicated section of time line. In your case, there was evidently so much going on in the time line with the large still images and the effects you applied to them, that FCP simply could not play it back properly in real time. By rendering that section, everything is rendered into a SINGLE FILE, which is what you see when you play the rendered section of the time line.

Render files can take up a huge amount of space on your media drives if you're not careful. And the heck of it is, you don't need ANY of them! Every day when I quit editing, I click to highlight the Library in the browser, click on FILE in the top tool bar, choose "Delete Generated Library Files," choose "All" and let 'er rip.

Render files are NOT needed for exports of your finished production. When you do an export, anything that needs "rendered" to play correctly in the output file gets rendered during the export. That's why I delete my render files every day. Just don't need 'em.

More info needed to help you diagnose. What are the photo details? Built-in scaling or 3rd party effect? Any differences between photos where the levels don't change during zoom? Does it happen in a new test library? Have you tried resetting FCP Settings? Hold down option+command when launching FCP. It will open the default Untitled library. Open the library you were working on, configure the Settings the way you like (disable background rendering, etc.) and see if the issue has been resolved.

Thanks for reporting back. That's good news it's only in the timeline. What if you render just that section? Manage render files in Final Cut Pro for Mac - Apple Support

Render a portion of your project: In the timeline, select the clip or clips that you want to render, then choose Modify > Render Selection (or press Control-R).

Does it occur in a new test library? Does it appear in the final output when exported/shared to a movie?

What are the exact details of the images that don't work compared to one that does? You can compare the EXIF info by opening the images in the Preview app. https://www.makeuseof.com/how-to-view-exif-metadata-on-mac/

Pull up the scopes, how much does it change there?

Actually, when you render the timeline, it can result in a series of very specialized files, not just one large one. Those "render" files are not typical video files. But yes, they can eat up tons of space needlessly. Turn background rendering off!

Are you set to playback with better performance, or playback with better quality?