I think the After Effects option of "Fit up to 100%" is a good idea. That way we always get to see the full video, bit it never get's upscaled, reducing quality.
Yes, After Effect's "Fit up to 100%" is sorely missing in Premiere! I put in a FR for this years ago, but think we could get the ball rolling on this one by all adding new FRs for this. I'll post my official FR for this in a new thread when I have the time.
By the way, what you suggest is a great idea James! After sending your FR, please copy it here so that we can copy/paste it and resend it to give it more 'weight'. There's power in numbers! I had also submitted a FR for this some time ago when I edited much more 720P material that I wanted toggled back to a 100% view rather than the default stretched 'fit to fill'. Now that I only edit FullHD on a FullHD monitor, my image is no longer stretched but rather shrunk when I tilde toggle out of full screen, so it isn't as much of a problem, but this option should certainly be added nonetheless for all those who still edit in any video resolution that's lower than their screen's resolution (which ends up in a lower quality, stretched preview of their Timeline by default, every time they toggle out of full screen, something that's very frustrating to say the least).
I have submitted this Feature Request this morning:
I would like to see "Fit up to 100%" as a display option for the Premiere Pro Source and Program Monitors, as it exists in After Effects. This would be especially helpful when using tilde to go back and forth from isolated and workspace views of the Program Monitor, ensuring the largest display that fits in the workspace, but also keeping the display, when isolated, from exceeding 100 percent.
Thanks to all,
I just submitted this FR to help support your case. Hope it helps!
*******Enhancement / FMR*********
Brief title for your desired feature: 'Fit up to 100%' display option in Source/Program monitors.
How would you like the feature to work?
1. The same way it does in After Effects!
2. When tilde toggling out of full screen view, the view setting the Source and Program monitor default back to should be 'Fit up to 100%' or 'Fit', depending on user selected preference in the Preferences window.
Why is this feature important to you?
Convenience! This feature is so convenient to have in After Effects that it's surprising that it still has not been adopted by Premiere Pro. Any image stretched beyond 100% loses picture quality, so for editors working with sub-FullHD resolution sequences on a FullHD+ monitor, a 'Fit up to 100%' view option would make it easy for them to always have their material displayed at the largest size possible without losing visible quality due to stretching.
Anyone reading this that agrees should copy/paste either this or James' FR and send it as their own. Power in numbers!