"Full Auto" overrides even the iris switch???
 

Do I understand this correctly? That if you put the camera in Full Auto, you can't override it by switching the iris to manual? And you can't have (for instance) a mix of manual & auto controls of gain, white balance, shutter speed, etc? I'm used to being able to pick and choose which functions I want to be in manual and which ones I want to be in auto. For instance, I might want the white balance to be in manual while gain is in auto, or have both in manual while the iris is in auto. But the HD100 looks like it's all-or-nothing (except for focus). Is this true???

Full Auto does exactly as described. It puts everything it can in auto - gain, iris, white balance. Frankly I don't know why JVC bothered putting such a button on a camera marketed as "professional," but I guess if you need to hand it to someone inexperienced in a cinema verité situation then they only need to worry about focus and framing.

The HD100 in NOT "all or nothing" when it comes to auto. You can customize auto functions to your liking just like any professional camera.

So first off, just turn the full auto switch off and never turn it on again.

Now, if you want auto iris, just flip auto iris switch from "M" to "A" just like on any pro camera. You can customize the "auto-exposure" behaviour by going into the CAMERA OPERATION menu and adjusting AE LEVEL. You can also assign AE LEVEL + or - to USER buttons 1 or 2 (by using SWITCH MODE menu) and then you can quickly adjust the AE level as you are shooting.

If you want auto gain (a.k.a. Auto Level Control or ALC,) go into "SWITCH MODE" in the menu and assign ALC to one of the gain switch postions. I would recommend using GAIN H. Now when you want ALC turned on, move the gain switch to H.
You can set the maximum gain limit of ALC by going into CAMERA OPERATION menu and setting ALC MAX. I think it defaults to +18dB. I would set it lower - maybe +12 would be more ideal.

If you want auto white balance (a.k.a. Full Auto White or FAW,) then go into SWITCH MODE menu, and assign FAW to one of the WB switch postions. I would recommend "B." Now when you want auto white balance turned on, just flip the white balance switch to B.

Thanks a bunch! You just clarified a lot for me.

JVC always had this option in it's professional range. Thank god the switch is all the way to the back on this camcorder....