Fire the boom mic operator!!

I’m sure it would be possible, but at extra cost - and what movie production company or distributor wants to pay to fix a problem that isn’t really a problem?

The “problem” is at the exhibition end, not the production end. If you are seeing the areas above or below the 1:1.85 image area, the theater is not properly framing the projector aperture and screen. It’s a mistake like having the frame line in the middle of the image, or an out of focus picture.

Now, some filmmakers do in fact use what is called a “hard matte” in the camera to block out all of the image except that 1:1.85 area. Sample image here. However, most production companies and distributors prefer not to do a hard matte because they want to retain the option of having a fuller 1:1.37 image for showing on standard television screens, without black bars appearing at the top and bottom of the image.

As you can see from the 35 mm frame diagram, the “television safe area”, while taller than the 1:1.85 theatrical image, still has unused areas at the top and bottom of the image where things like boom mikes can remain safely hidden.

So, to sum it up, 35 mm images are framed not according to what the camera aperture can see, but according to what the theater or television audience will see. If you are seeing things like boom mikes, the fault is with the exhibitor, not the producer.