Backfires are not a certainty. You can watch a replay 10 times and sometimes you get the visual effects and sometimes you don't. I found this out trying to capture backfires in photo mode. Spent literally hours trying to capture a backfire.
Also, backfires are treated the same as Sparks so you cannot properly "freeze" the backfire in a photo, it will always have a blurred effect like Sparks. Unless they patched it to behave differently recently.
