Broadly speaking with the GH5 as well as with any other camera you have four categories of close up work:

1. Close-up – frame size 10 cm or 4″ and wider typically hand held
2. Super close-up – frame size 5cm or 2″ preferably on tripod
3. Macro – frame size below 2″ only on tripod
4. Super macro – frame size below 1″

For still images a typical choice is the Olympus 60mm, this lens however is very narrow so for any subject that is not too small and for the first category of close up you end up having working distances well above one foot. This in turns means more water to go through and makes it virtually impossible to cover larger subjects.

If you make that choice is because you have skittish subjects that do not like proximity and are very small. Furthermore the Olympus 60mm has not stabilisation and therefore with our GH5 will only use in-body stabilisation. Another side effect of using this lens is that it is impossible to take shots of divers or anything else at medium range so the videos end up being a collection of very close shots that may please someone but result fairly boring.

Of course you can make this kind of video exciting to an extent like here

But at the end for me something like this is more fun although of course the quality is very different (I shot this years ago with a Panasonic LX7 and edited in iMovie)

The difference between the stunning video of Dustin and the basic video of mine is that you only have very close shots in the first one and frankly a slideshow of still images would be equally nice. There is no description of any sort of where is the fish what are the conditions or anything at all. You may argue that the stuff to see is not that nice but at the end this gives you a real idea of the diving where you go which is the purpose of my videos and majority of non Pro people. Furthermore medium size subjects that move like octopus, squids, crabs will almost always exhibit some kind of behaviour.

My macro video rig is built around the Panasonic 14-42 MKII which is the same lens I use for wide angle video with the Nauticam WWL-1. In effect am running video like a compact set up.

Ergonomics and lens

1. The field of view with at 42mm is only 23 degrees horizontal and 13 degrees height this is ideal for portrait type of work
2. I still use my old Sola 1200 video lights that can be used with a 20 degree beam creating a snoot like effect to better isolate your subject. It can be argued that color rendering index of newer lights is better but I think the narrow coverage of the lights is more important. Consider that at wide end the field of view is less than 60 degrees anyway with the flat port at 18mm
3. I use two close-up lenses with a Saga dual flip diopter
4. The rig as described is heavy in water more than 700 grams negative to ensure the required stability
5. The tripod base has 2x 3″ segments and 1x 5″ segment to be as close as possible to the bottom this creates issue if you do not have a monitor as you need to have your face in the sand however once the shot is framed all is good

Close-up lenses

I use two close up lenses with this rig as the 14-42mm as a working distance in water around 26cm and a minimum frame size around 9cm that is pretty wide.

The SubSee 5 is in the sweet spot for the 14-42mm lens because it starts working pretty much when the 14-42mm can-t focus anymore and down to around 10-12 cm working distance. Minimum frame size is 46 mm

Using the Ex-Tele feature in video means we can get to 33mm which is below the 36mm classic DSLR 1:1

When this is insufficient and the subjects are really tiny the next lens is the Nauticam CMC-2

The CMC-2 gives a frame size of 32mm as in this image

Using Ex-tele this becomes 23mm which is the same you get with the CMC-1 without ex-tele and is plenty for any purpose. It is theoretically possible to stack the two close up lenses but is not really necessary and the working distance too small. The CMC-2 works around 6-7 cm so you have still space for lights etc.

Olympus 60mm

Is there any use for this lens? Of course there is in case you want to capture a frame smaller than 23mm with the 60mm you can get down to 17mm with the bare lens to 12mm with the Ex tele, 9 mm with the CMC-1 and 6 mm with CMC-1 and ex tele. Will you be able to focus and work with the CMC-2 at 22mm from the subject is another discussion however for skittish subjects it gives you more working distance and this may be needed. I would recommend taking this lens with you for those cases but for video I do not see how you can really use the CMC-1. Please note the CMC-2 is useless with the 60mm as the working distance improvement is minimal to none.