Frankie…
when you have 2 clips straight cut back to back on the same track, you full exposing your selected frames on both clips.
By definition, therefore, when you add a transition you will in some way be exposing frames that were not previously exposed based on your original markings
Let’s use 1 sec transition (ntsc)
Applied centered, it will expose 15 frames more of the outgoing shot and 15 frames more of if the incoming shot.
Applied ending at cut, it will expose 1 sec more frames of the incoming shot.
Applied starting at cut, it will expose 1 sec more frames of the outgoing clip.
It has to, in oder to create the effect, it has to use additional media.
so you have 2 choices.
when rough cutting, plan for fx, so wherever you’d normally set you IN add 15 frames then mark in. where you’d set your out, subtract 10 frames, then mark out.
Lay the edits on the time line back to back, then when you add the transition you’ll get what you want.
or
Lay the edits on alternating tracks and overlap them the way you like, then add the transition on the higher track.
This is not a Premiere thing, it’s just the way same track video editing works.
That’s one of the reasons film editors thought video editing was so sloppy back in the early days..you were never sure what you were gonna get.
Hope that helps,
Alex Udell
Editing, Motion Graphics, and Visual FX
Younversity TV
http://www.youniversity.tv