underwater housing for nx1

If you are a handyman, you can do yourself a case for camera, similar one for a separate flashlight and for underwater it should be on a side (or both sides) about 1-2 feet away.
It is much simple since on NX1 you have AutoFocus on camera and a triggering solution by an USB wire.

You need a piece of large drainage tube, about 25-30cm = 10-12" diameter and 6-12mm = 1/4 - 1/2" thick, two transparent plexiglass circular plates to cover front & back 6-8mm = 1/4 - 1/3" thich, some long screws with nuts, access to a lathe or you can do it manually but more work.

Have a look at my drawing below.

some drawing for an underwater case

The pipe has a diameter and length to host the camera - maybe with the flashlight up.
You need too paralel and plane cuts, then to dig / scratch a channel on front / rear planes for silicone glue to made sealing rings presses by the plexiglass plates.

The two plexiglasses have diameters with 25-50mm = 1-2" larger than the pipe, so you can have on outside the pipe a series of screws and nuts to fix and seal the case from plate to plate.

No lathe, then you need quality hand work, but you can do it easy.

You need to program camera for AF - maybe central area, pass the USB cable through a hole in the pipe and seal with a lot of silicon on the outside (we used to seal mechanical, more complex...).
You also need to seal the trigger...

If external flashlight, now everything is complex, but you can have it manual to a certain energy (power) and test what aperture is OK for certain distance flash-subject.
Once upon a time, you could program this on flash, but with digital this have moved to camera and underwater I do not know how radio synchronization is working, also you can have it done by a cable too.