Hi everyone,

this March I’ll finally fulfill my dream of traveling to Raja Ampat - reason enough to consider a small additional purchase 😄.

Up to now I’ve been shooting with my compact setup: RX100 VA / S-220 + SF01 / Inon UWL-95S + Dome for wide-angle work.

However, I’d also like to capture close-up shots — not just “true macro” but also detail shots of larger subjects.

My question is: when it comes to close-ups, is this realistically achievable with the RX100 in terms of working distance to the subject? Or will the working distance be too short to make it practical? Especially when freediving?

Since I’m currently using the XD-Mount system, I’ve been looking at the INON UCL-90 XD (+11) and the UCL-165 (+6), but I’m completely open to other suggestions — I can use an XD-Mount adapter if needed.

Thanks in advance for your insights!

The working distance is relatively short with the RX-100, Nauticam publishes the magnifications and working distances achieved with their close up lenses here:

Google Docs

N50 & Compact System 2025-06-20.pdf

The CMC-1 is close to the UCL-67 in power, while the CMC-2 is close to the UCL-90 lens. The CMC-2 at max magnification covers 48 x 32 mm, which is about 0.75x, so getting close to what you can achieve with a 1:1 macro lens on full frame, however it only focuses between 80 and 124 mm. The RX-100 alone covers about 100mm across the frame, so the UCL-165 will achieve somewhere between that and what the CMC-2 will achieve.

I would guess that the UCL-165 is probably quite usable and could fill the frame with small subjects you could expect to be able to find in the relatively short time you have on the bottom free-diving. The issue I find with closeup photography is that finding the subject is hard part for small subjects, while 30-40mm nudis etc are generally a lot easier to spot. You would be the best judge about your ability to approach and shoot objects at the distances we are talking about.

I second what @Chris Ross writes, thoughtfully.

@Chris Ross@humu9679

Thanks to both of you (I didn't know, that there was such a chart).

I didn’t express myself very clearly – I’d like to use it for freediving, but also for scuba diving. Would it still be advisable to start with the UCL-165, since the greater working distance makes it easier for getting started?

As for freediving, what I usually do is use the first dive just to look at and choose what I want to photograph, and then on the second dive I take the actual shot.

Exceptions apply, of course :-D.

Edited 10 hours ago10 hr by Apneagraph

2 minutes ago, Apneagraph said:

@Chris Ross@humu9679

Thanks to both of you (I didn't know, that there was such a chart).

I didn’t express myself very clearly – I’d like to use it for freediving, but also for scuba diving. Would it still be advisable to start with the UCL-165, since the greater working distance makes it easier for getting started?

As for freediving, what I usually do is use the first dive just to look at and choose what I want to photograph, and then on the second dive I take the actual shot.

Exceptions apply, of course :-D.

The problem with wet macro lenses is the very limited range they actually focus in, however the weaker they are the wider this range. This is a problem as it can make getting what you want in focus tricky sometimes.

As to what to start with this depends on what size critters you manage to find usually. With the UCL90 assuming equivalency with the CMC-2, you can shoot portraits of critters that are around 35-70mm long (filling 70% of frame in horizontal axis) at a guesstimate based upon the working distance range provided. It seems that the UCL-90 is something like 10% more magnification than the CMC-2 It is also reported that the UCL-90 gives more working distance than the Nauticam CMC-2.

It's reported that the the frame at min focus distance for the RX-100 is 100mm across so through a flat port would cover 130mm so it would be usable for 90-100mm long subject without the close up lens. You can check what the bare lens can do for yourself on land, I only found a random internet post with data. Note that land based measurements need to be corrected for flat port magnification, while I believe the Nauticam data already covers this.

This leaves a gap for objects 70-90mm long, but you could probably handle that with cropping the bare lens or maybe zooming out a little with the UCL-90, assuming the Nauticam data is for the lens at maximum zoom.

It seems like the UCL-90 might provide a reasonable range of subjects sizes without needing to get too close. Also assumes your subjects you find won't try and leave (like fish and other mobile animals).

For reference this video shows testing results for the CMC 1 and 2 and the UCL 67 and 90 lenses. IT is tested with a different lens but the relative performance will be similar for your lens, so the relative differences in magnification and working distance will be about the same.

6 hours ago, Apneagraph said:

@Chris Ross@humu9679

Thanks to both of you (I didn't know, that there was such a chart).

I didn’t express myself very clearly – I’d like to use it for freediving, but also for scuba diving. Would it still be advisable to start with the UCL-165, since the greater working distance makes it easier for getting started?

As for freediving, what I usually do is use the first dive just to look at and choose what I want to photograph, and then on the second dive I take the actual shot.

Exceptions apply, of course :-D.

I understood you wanted to free dive doing this. And I do think photos/video would be made easier using a less magnifying lens, like the UCL-165 (I quite like these, and you can stack them), and also the CMC-2. The CMC-1, which I also own, can be a cantankerous little monster, so I wouldn’t use that unless I had more time to wrestle with it. I’ve not tried the UCL-90.

If a bigger focus range is what you are looking for, then the small AOI UCL-05N could be a valid option:

https://www.aoi-uw.com/products/wet-lenses/aoi-ucl-05n.html

It's the same as the old Fantasea UCL-05LF 6. Here a comparison test:

Wildlife in the Balance

Review of Fantasea UCL-05LF 6 Macro Lens - Wildlife in th...

Review of Fantasea UCL-05LF compared to Inon and Dyron lenses. The Fantasea outperforms in almost all cases.

Unconventional thought:

A wet wide lens with zoom through capabilities is something I use with a 26-95mm FF equivalent lens for smallish creatures. Yes it's not macro but it's also a lot faster to acquire and focus.

Edited 52 minutes ago52 min by Grantmac

7 minutes ago, Grantmac said:

Unconventional thought:

A wet wide lens with zoom through capabilities is something I use with a 26-95mm FF equivalent lens for smallish creatures. Yes it's not macro but it's also a lot faster to acquire and focus.

Love the lighting on that pic. Film noir stuff!