Are the OM-1 or GH6 good upgrade options for underwater stills?

DK Underwater wrote:

I find pictures with epl 10 to be not very sharp, perhaps its the auto focus that is lacking making it difficult to get sharper images.

my girlfriend recently got a sony a6600 with a 90mm 2.8 macro lens and I find that the pictures I get when using her camera is significantly better.

The better AF on the om-1 may just be what is needed.

All things equal, 'focus' on the larger APC sensor is slightly harder due to the reduction in depth of field.   But there are so many other variables in play.

What F-stop are you using on the Pen?   And what method used to get the focus and then pull the shutter?

You want to rely on your strobes for lighting, and keep the lens itself pretty closed to maximize the depth and to remove the background.  If you're shooting at f/4, it won't be as sharp.

On the GH4, I employ the back focus button and then just push/pull the camera while watching the screen.   This is a poor man's version of getting the manual focus gears.  The shutter pull on the nauticam is a very easy one, so I'm not torquing the housing when doing it.   In contrast, on my wife's G7X compact housing (also nauticam), it takes a more forceful pull.

One way you could test for this is to use the timer, though it still relies on you keeping the distance to the subject still (or tripod it).   If you could do a practice session in a pool, you could prop it on a brick or tripod.

It may well be that the higher end 4/3rds will make it easier to get good focus, but you want to explore the methods you do have control over to ensure it won't just be the same problems several thousand dollars later.

Also note that the 90mm on APC is 135mm equil, while the 60 on the 4/3 is 120.   Both are pretty aggressive versus the traditional 60 on APC or 100 on FF.