I tell them how I want it shot and what angles, and we got a storyboard. I also check the camera and audio recorder settings beforehand. But you think that changing the exposure during the shoot is obvious, which is why I didn't think to mention it. I mean these friends, have seen movies before, and that's just not accepted.
Well I will have a talk and try not to be too bossy. But if they don't listen they are going to ruin this short! Either that or I will fix it all in post hopefully.
I'm late to the thread as usual, but since no one else mentioned it I thought I'd chime in on the text I put in bold above:
In your original post you mentioned that the exposure changes occurred during a zoom, welcome to the unintended side-effects of using "less expensive" (eschewing the word cheap here) zoom lenses, which do not have a constant aperture rating throughout their focal length range.
Say your lens is described as being "f3.5-5.6" or something similar, this means that the max aperture possible on the lens changes as focal length changes (zoom). Your DP should be aware of this fact and should be able to determine how much range you have on the lens before the max aperture value starts to change.
For example, I recently rented a 14-150 Olympus m4/3 lens (which I ended up disliking very much) that was f4-5.6. (it was for stills) At the extreme ends of the lens (14-20ish and 100-150 or so) it started to close down to the 5.6 rating. In between it would stay at a 4. The numbers are for example only. The point is that if you are absolutely married to using a zoom in one or more of your shots, there should be a range on the lens where it won't change mid-zoom. Usually in the middle of the available range somewhere. On some zooms they only go slower at one end or the other, but not both. The best (most expensive) ones are constant, meaning they will hold their fastest aperture throughout the zoom range.
Also, when executing a zoom ALWAYS set your focus at the longest end of the zoom, where it is the most critical, your DP should know this as well.
As far as her getting defensive and telling you that you worry too much - that's not acceptable behavior for a DP. She should be MORE concerned about the quality of each and every shot than you are because it is her job.
Finally, a note on pulling exposure: I've done some of these, but never for "artistic" reasons. Exposure pulls, in my admittedly humble experience, are reserved when some kind of camera move necessitates opening or closing the lens because of changes in lighting across the move. Example:
A drug dealer has a trailer hidden in a forest and is inside counting his money on a sunny day. The director wants to pan down from the sunlight in the trees and reveal the dealer inside the trailer. You need a 2.8 to get a good exposure on the trailer interior, and you need an 5.6-8 split to expose the sunny trees to your liking. (again numbers are for illustration only, not actual exposure values which would vary depending on a number of factors) During the pan you gently pull the exposure with the move, hopefully right around the moment the wall of the trailer is passing frame (where the pull can be best hidden).
The fun part for a 1AC is when you're pulling focus and aperture at the same time.
Edit:
Stop saying "Fix It in Post." That phrase is a joke for a reason. Be firm, but diplomatic. If necessary, "Grow a Pair" (as CF suggested) and fire the ones who aren't working out. Confidence will come with experience, and these things will come easier if you stick with it.