The most common and most likely answer to this crossword clue is the 8 letter word SHOOTING
I've seen this crossword clue in The Daily Telegraph
S
H
O
O
T
I
N
G
Buddy explains!

The straight part
We know that "Filming" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case filming = shooting.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SHOOTING mean?
SHOOTING verb- To launch a projectile.
- To move or act quickly or suddenly.
- To act or achieve.
- To measure the distance and direction to (a point).
- To inject a drug (such as heroin) intravenously.
- To develop, move forward.
- To protrude; to jut; to project; to extend.
- To plane straight; to fit by planing.
- To variegate as if by sprinkling or intermingling; to color in spots or patches.W
- To shoot the moon.
- An instance of shooting with a gun or other weapon.
- The sport or activity of firing a gun or other weapon.
- A district in which people have the right to kill game with firearms.
- The act of one who, or that which, shoots.
- A sensation of darting pain.