Having purchased a Sony a6400, I knew it would require accessories to maximize its potential as a video camera to compliment my Sony FS7 M2 as a B-camera.
I had been interested in an a6300 in 2016, but then the 2019-released a6400 really spoke to me as it had been upgraded from the a6300 to do video really well without overheating, but it also didn’t have a bunch of bells and whistles I didn’t need like the a6600 does. The a6400 also has a very nice flip-screen which is only helping to entice me to create my own YouTube channel vlog. However, once I was comfortable enough to buy one a month ago, I was saddened to see that a6400 body-only was not in stock anywhere, including B&H. However, I was very pleased to find it in stock at Precision Camera during my recent trip to Austin. I got the 6400L kit which includes a Sony E PZ 16-50mm f/3.5-5.6 OSS lens at the same price as the body by itself. Score.
Front 
Rear 
Underneath
I already had a few items for the camera in my B&H wishlist, so the first item I purchased was the SmallRig 2310 (not 2310B) cage. The 2310 does not have built-in cold shoes like the 2310B does, however, the 2310 does have mounting points to support lens mount adapters such as those made by Metabones. It sucks using lens mount adapters on a body that doesn’t have a positive lock, so affixing the adapter to body via the cage will eliminate unwanted lens rotation during focus pulls or manual zooms.
It sucked removing these from the camera. 
One of them got me.
To install the cage, I first had to remove the little metal triangles and plastic protectors that are intended for the camera’s neck strap. That was a gigantic PITA at first and I eventually had to use a small screwdriver as crowbar. Unfortunately, one of the metal bits got me under a fingernail and I bled a bit. Nothing crazy, but it was not a gentle experience. Once they were off, I could mate the camera to its cage.
The SmallRig kit comes with this tiny hex screw and a tiny hex key. Fitting the a6400 into the cage and taking care of this screw was a breeze.
The a6400 is now ready to be buried underneath a bunch of videography equipment that it wasn’t really intended for! Next on my list of add-ons is a top handle for run-and-gun work, an offset cold shoe for mounting a mic for vlogging, and an adapter to affix to lens mount adapters as mentioned earlier. Of course the camera looks a little silly riding on the back of a lens like the Sony FE PZ 28-135 F4 G OSS, but the potential for capturing very nice Slog3 8-bit 4:2:0 video with this camera is a real possibility, and this sturdy little cage from SmallRig not only enhances it’s moddability for any situation I might need it, but it also protects the camera itself.
How have you modded your a6400 for video? Let me know in the comments below.
