ok so it appears locking the screen makes it keep the camera app ready to shoot a new photo without the chance of a camera initialization error, this seems to happen with Vignette, Camera 360 etc. if you power off the phone with the camera running. The camera won't keep the phone on forever, just 2 minutes (a lot for the screen to be staying on especially if you are doing this with the screen on full bright) and then it will kick you back to the launcher and time out and turn off based on your system settings. I guess this is all necessary to avoid camera initialization errors and keep the camera ready to shoot. So it is making sense to me now, but this isn't ideal, it still leaves some time where the phone could be on and susceptible to random screen taps while in a pocket etc and stay on (in thin shirts pockets with the screen facing my chest triggers the screen).
After trying the other available camera apps, the default camera seems the most stable and quickest to take photos, with the other apps being good for post-processing duties. I just wish that power button could be re-purposed as a shutter button, and let me use a soft key to lock the screen. As it is I am going to practice resting my finger on the power key to keep it out of the way of the lens.
I find my camera phone to be my main camera since it is nearly always available, so I really want the camera to work out. I'm even considering a head-mounted flashlight for indoor shooting, just keep it in my bag for the occasions where it may be necessary
I'm such a dork.