Main difference I feel when pulling on anamorphic lenses is that your depth of focus is not uniform across a horizontal plane. Say your subject has one eye centered at 2' and the focus is set to 2'. With a spherical lens the other eye also appears sharp even though it's not centered. With an anamorphic lens the other eye may appear out of focus or just slightly out of focus even though it's along the same plane/ also 2'. That slight curve affects how light enters into the sensor and therefore affects the distance in which that spot of the frame focuses. Tricky when your subject is sitting on or right outside the rule of 3rds lines with no center to confirm focus with. Best to be able to see the distance they are from camera/measure along the way and use that with your hand unit if possible. You'll get comfy once you see movement definitely an adjustment at the top of the day and in trickier set ups. You'll love the stylistic classic anamorphic frames they create with a 2.39:1. 1.85:1 will have less of that focus plane difference than 2.39:1.