When working with a 4K source, if you have no need or intention of creating a 4K output file, then editing in a 1080p sequence is just fine. In fact, that gives you some leeway to do cropping, and virtual zooms and pans (keyframed) if need be to reframe the footage. But yes the relationship between footage, sequence, and export is definitely very important, but the workflow depends on your unique situation. As a rule of thumb, the sequence resolution should not be less than what you want to export to or that will decrease quality. For instance, editing 4K footage in a 1080 sequence when you intend to output as 4K, you are "dumbing down" the 4K quality to HD quality then and do not get the full 4K quality back on the export, it is gone. Thanks Jeff
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