Canon Powershot S120 vs G16 for macro

I'm an inexperienced amateur underwater photographer, and I'm interested in buying a new compact camera, my main interest being underwater macro photography (e.g. of nudibranchs). For reasons of budget and of specs, I've narrowed it down to a couple of models: Canon Powershot S120 and Canon Powershot G16, and I was hoping to get some help deciding which one to buy.

The G16 is clearly the better model for my purpose, with a minimum of 1 cm focusing distance (against the 3 cm of the S120). Although it would be hard to get this close to a subject underwater, I seem to understand that a shorter min focusing distance means it is in general easier to get a good macro shot (for example in terms of focus speed).

The S120 is much more versatile, as it is smaller and has touch screen. It is also cheaper, and housings are cheaper.

The type of advice I am looking for is for someone to quantify exactly how much better the G16 is at taking underwater macro shots than the S120. I'm hoping for the gap to be small enough to justify me buying the S120, and I would also consider getting the ikelite housing with the wet-mountable add on macro lens to get the magnification I need. But since macro photography is the main reason I'm buying this camera, if the G16 takes considerably better shots than the S120 (considering, of course, they can be both be upgraded with the above-mentioned lens), I would go with the G16 despite the increased bulk and higher pricetag.

Thank you very much for any advice!

Not much difference the image processor is the same. As the G series have more zoom once you add a close up lens subjects looks a bit bigger but not so much compared to the S series. Image quality wise really not much in it at all in fact DXOmark rates the S120 better than the G16 both in terms of dynamic range and ISO but the difference is minuscule

As the G series have more zoom once you add a close up lens subjects looks a bit bigger but not so much compared to the S series.

Do you mean optical zoom? They both have a 5x optical zoom. Also I think I read somewhere that the closest macro shots can be taken without any zoom... can you elaborate on how adding a close up lens has to do with the zoom?

Thanks a lot for you help

Ignore completely the close focusing distance you don't shoot fish at less than 10 anyway

You are not going to shoot macro without an add on lens. You use a close up lens and then you zoom to the max for magnification. The g series are 140mm equivalent the S are 120mm equivalent so a bit less

All in all not much in it on land some Of the G series feature are useful underwater the S cameras are more versatile