With the Hy6 and Hy6 Mod2 its very convenient to program the autofocus to work with a different button than the trigger. Here's how you do it: Just set your AF slider switch to the end of travel at the red button, then press and keep holding down the button just above the AF slider (Button #53 in the picture) and adjust the scroll wheel on top of the grip until the display shows Focus - Manual as shown in picture, then release. Done! Now when you want to turn on focusing just press this same button #53 above the slider and it will activate the focus when depressed and the shutter button will only trigger the shutter.
When you want to go back to normal AF operations with AF on the shutter trigger half press, just switch the AF slider to whatever setting you like. Once you have configured the custom mode you can always go back and it will be the where you had it. This is convenient since the custom mode red area is always at the end of the slider travel so you never need to look at it, you can just move the slider to the end and know you have it. Nice ergonomics right!
Note that you can also use this custom mode to set the AF to continuous or to an AF lock mode (where you can't take a picture without having focus lock). All of this is in the Hy6 user manual under custom AF modes.