The built-in mic in Canon DSLRs is very susceptible to wind noise. If you want to maximize the usability of that audio (for scratch/synch or otherwise), here’s a DIY tutorial on how to make a “deadcat” wind muffler for the mic. In a nutshell, it simply requires modifying Rycote Overcovers and applying with some double-sided adhesive. Here’s a before and after video that illustrates the difference a good deadcat windscreen makes. Watch below.

5D Mark II Wind Muff from Zack McTee on Vimeo.

(Via DSLRVideoShooter)