![[Kyotaro's Underwater Photography School] SONY RX100 or Olympus TG-6? How to Choose?](/_images/e994cb963efa-1440w.webp)
The Editor says: Among today's many underwater photographers, Kyotaro stands out for his ability to produce stunning shot after stunning shot with relatively affordable, streamlined gear. Already an accomplished topside photographer, he has a uniquely insightful grasp of the relationship between aperture, shutter speed, and ISO. He hopes that through hands-on workshop instruction, he can help everyone avoid the pitfalls he once faced. If you'd like to join Kyotaro's underwater photography workshop, click here! This article is reproduced in full with the author's permission from the author's Facebook.
This is by far the question I get asked most often — both in my underwater photography courses and in everyday conversation. As someone who has personally used the RX100 M3 and M5, as well as the TG-1, TG-3, TG-4, TG-5, and TG-6, I'll do my best to stay neutral and share my personal experience for anyone having trouble deciding. 
:)
The following is a point-by-point breakdown, with items listed in the order I personally prioritize them.
【Where the RX Outperforms the TG】
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Image quality: Directly tied to sensor size and lens assembly size — this is the single most important factor for those who ultimately choose the RX series.
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Exposure modes: Offers a full suite of A (Aperture Priority), S (Shutter Priority), and M (Manual) exposure modes.
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Controls: Uses a dial/wheel adjustment system for aperture and shutter speed, making exposure changes highly efficient — on land, at least.
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Autofocus speed: The RX100 M5's autofocus is genuinely blazing fast.
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Wide-angle end: Every millimeter counts in wide-angle shooting, and the RX edges ahead of the TG series with an equivalent focal length of 24mm.
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4K video: From the RX100 M4 onward, 4K recording is available and the quality is exceptional — especially for macro video. The TG-5 and later also offer 4K, but they're simply not in the same league; the difference is substantial.
【Drawbacks of the RX】
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Adjusting shutter speed in M mode: Because aperture and shutter are controlled via a dial-and-wheel combination, the system is very efficient on land — but once you install the underwater housing, the dial becomes inaccessible. To adjust shutter speed, you have to switch to Shutter Priority mode, make the change, then switch back to M mode. If you need to adjust again, you repeat the whole process. This workflow is genuinely painful underwater. ※Some housings do not have this issue.
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No manual flash output control: On Sony cameras below the APS-C class, flash is locked to TTL — you can only adjust flash exposure compensation (±3EV). This has a measurable impact on continuous shooting with an external strobe (battery drain, longer recycle time, and shutter-release lag).
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Size: Due to the RX's periscope-style lens design, its underwater housing is inevitably much bulkier than the TG's.
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Battery life: The camera's powerful performance — the "advantage" of ultra-fast autofocus, the "advantage" of forced TTL flash, and so on — comes at a serious cost to battery endurance.
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Shutter lag: When the flash is enabled, the shutter-release delay while the strobe recycles is genuinely unbearable for me.
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Macro: The RX series' strength is its 1-inch sensor — but the larger the sensor, the more minimum focus distance and magnification ratio are compromised. At that point, you may need to invest in a separate macro lens (more money).
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Water resistance: The RX offers zero waterproofing whatsoever. Don't ask me how I know this — I'll cry.
【Where the TG Outperforms the RX】
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Macro: The TG can shoot macro subjects without any additional lens attachments, so you can travel lighter with one less accessory. Moreover, beginners using the TG will achieve a much higher success rate with macro than those using the RX100 with a macro lens.
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Water resistance: My dive history isn't that long, but I've already flooded NT$140,000 worth of gear. Having a waterproof body is genuinely reassuring, and swapping batteries topside is far less nerve-wracking.
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Size: Even with the housing on, the TG is small enough that I can easily slip it into a BC pocket — something the RX series simply cannot do. When I'm shooting with a large DSLR as my primary camera, the TG is always my go-to backup. The compact form factor is also a huge convenience for instructors who want to dive relaxed while keeping an eye on students.
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Cost of entry: Both the TG body and its housing are cheaper than the RX equivalents, and the macro lens for the RX is an additional significant expense. All in, the RX system costs more than twice as much as the TG.
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Manual flash output: You can dial the strobe output down to 1/64, which greatly helps with battery life, recycle speed, and power management during continuous external strobe shooting.
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Battery life: In my personal usage pattern, the TG consistently lasts 1–2 additional tank fills compared to the RX.
【Drawbacks of the TG】
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Image quality and resolution: This is the most common reason people abandon the TG for the RX — it's simply the fate of a small-sensor camera.
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No full manual exposure modes: I've previously shared a hidden M-mode workaround for the TG-6, but the fact remains that the TG doesn't natively offer M mode or S mode. Even A mode only provides 3 steps of adjustment, which can be genuinely frustrating for more advanced shooters.
【Other Considerations】 (no winner declared)
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Underwater white balance / color rendering: Both cameras offer underwater white balance, but their color profiles are quite different, and each has its own fans. Personally, I find Sony's files easier for beginners to color-correct in post. Olympus applies more in-camera color processing, so straight-out-of-camera shots may look more pleasing, but getting serious about color grading requires more effort.
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Sensor aspect ratio: The RX shoots in 3
; the TG in 4. Having shot for many years, I personally prefer the traditional 3 ratio reminiscent of film.
Conclusion: Every system has its own strengths. What we need to do is accept the limitations of the camera in our hands and make the most of its advantages. ※ I have no affiliation with any brand and receive no sponsorship. This is purely a personal experience share — brand loyalists, please don't come looking for a fight. Choosing a camera shouldn't have to be a tribal war.
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