Sea & Sea YS-D2

Manufacturer: Sea & Sea
Type: strobe
Year introduced: 2015
Guide number: GN 32 (land, ISO 100); GN 24 with 100° diffuser; GN 20 with 120° diffuser
Color temperature: 5250°K
Batteries: 4x AA (NiMH or alkaline)
Recycle time: 1.5 seconds (NiMH)
Flashes per charge: ~200 (NiMH)
Triggering: Nikonos 5-pin sync cord or fiber optic
Depth rating: not specified (predecessor YS-D1 rated to 100m)
U.S. retail price: $719.95 (original YS-D2); $689.95 (YS-D2J)

Overview

The Sea & Sea YS-D2 is a TTL-capable underwater strobe announced on July 2, 2015 as the successor to the YS-D1 (^[1]). Marketed as the “Next Generation” strobe, it retained the YS-D1’s power output and DS-TTL II protocol while adding several ergonomic and functional improvements. It began shipping on July 15, 2015 at a U.S. retail price of $719.95 (^[2]).

The YS-D2 became one of the most widely used strobes in underwater photography during the mid-to-late 2010s, but its reputation was severely damaged by persistent reliability problems in the original Chinese-manufactured version. Reports of flash tube failures, circuit board defects, flooding, and optical sensor sensitivity issues circulated extensively through the Wetpixel community. Sea & Sea responded in October 2017 by releasing the YS-D2J, a Japanese-manufactured version intended to address these quality control problems (^[3]). The strobe was eventually succeeded by the YS-D3 Lightning in April 2020 (^[4]).

New Features Over YS-D1

The YS-D2 was positioned as an evolutionary upgrade over the YS-D1 with the following improvements (^[5]):

• Audible confirmation — beep sounds for TTL confirmation and ready-light confirmation
• Rear glowing panel — backlit control panel with easy-to-read controls, useful for night diving
• New control knobs — redesigned from the YS-D1’s controls, which some users found too easy to accidentally bump (^[6])
• Dual-powered target light with red filters for focusing in low-light conditions
• Wing nut style fixing bolt for easier arm attachment
• Newly designed battery compartment
• Faster recycling time compared to the YS-D1 (^[7])

Included accessories were a diffuser (100° and 120° versions), diffuser straps, red filters, ball mount strobe adaptor, M4 hexagon wrench, and the new fixing bolt (^[8]).

Exposure Modes

The YS-D2 supported multiple exposure modes, indicated by colored backlight on the rear panel:

• DS-TTL II (light blue indicator) — Sea & Sea’s proprietary TTL protocol, supporting slave TTL and slave manual modes
• Manual with pre-flash (double lightning bolt setting) — for cameras that fire a mandatory pre-flash
• Manual without pre-flash (single lightning bolt, green indicator) — standard manual mode
• Slave TTL (dark blue indicator) — optical slave with TTL capability

A common user error involved mismatching the camera’s flash mode with the strobe’s mode setting, particularly with compact cameras that fired mandatory pre-flashes, causing the strobe to fire out of sync with the shutter (^[9]; ^[10]).

Variants

YS-D2 (Original, 2015)

The original YS-D2 was manufactured in China and began shipping in July 2015 at $719.95. Available in black. This version developed a poor reputation for reliability issues (see Quality and Reliability Problems below) (^[11]).

YS-D2J (Japanese-manufactured, 2017)

Announced October 3, 2017 and priced at $689.95 — notably $30 less than the original. The “J” designation explicitly indicated Japanese manufacture. The specifications and features were identical to the original YS-D2. The Wetpixel announcement article directly linked to the community ^[12], noting “there have been reports of reliability issues with the original version and it seems the release of the YS-D2J is in response to this” (^[13]). Available in yellow, which served as a visual distinction from the black Chinese-manufactured units. Community members specifically advised buyers to ensure they received the yellow YS-D2J variant (^[14]).

Quality and Reliability Problems

The YS-D2’s reliability issues became one of the most discussed strobe problems on Wetpixel during 2016-2019. Multiple distinct failure modes were reported across numerous forum threads:

Flash Tube Failures

The most serious and widely reported issue. Flash tubes would shatter or disintegrate inside the strobe housing, sometimes after relatively few dives. This problem was inherited from the YS-D1 and was not addressed in the YS-D2 redesign (^[15]).

• One user reported flash tube explosion after only 15 shots at 3/4 power over 10 minutes, on a strobe only 9 months old. The same user had previously experienced flash tube explosions on two YS-D1 strobes (^[16]).
• A user found “the flash tube in one strobe was just a pile of powder inside the housing” after 300 dives and 15 months of use (^[17]).
• Backscatter reported testing a returned unit and finding “something was wrong with the strobe’s system where it was dumping full output into the bulb, so replacing the bulb would just eventually end up bursting again” (^[18]).
• Sea & Sea’s explanation was that the flash tubes were “taken from conventional land based flash units” and not designed for the sealed, heat-trapping environment of an underwater strobe housing. Users were advised not to fire more than 10 shots at high power in succession and to wait 10 minutes for cooling (^[19]).

Disputed: Sea & Sea’s position that flash tube failures were not covered under warranty conflicted with the experience of several users who successfully obtained warranty replacements. Flash tube replacement cost over $200 out of warranty (^[20]; ^[21]).

Circuit Board Defects

One user’s brand-new YS-D2 failed after only 3 dives — it would not turn on at all. Sea & Sea Japan’s diagnosis was that “few parts were defective, whole main circuit board has become broken” and noted “this is not rare” (^[22]).

Depth-Related Failures

A user in Malaysia reported that both brand-new YS-D2 strobes would fire normally on the surface but fail at depths of 15-20 meters, firing only 10-15 times before shutting down with blinking warning lights. The problem was reproducible across multiple dives. Sea & Sea Japan could not replicate the issue in a pressure chamber (^[23]).

Optical Sensor Sensitivity

The YS-D2 was widely reported to have poor sensitivity on its fiber optic trigger sensor compared to the YS-D1. Users frequently found that the YS-D2 would not reliably trigger via fiber optic connection directly from housing flash triggers, even when the YS-D1 worked perfectly with the same cables and setup. Daisy-chaining the YS-D2 off a YS-D1’s output port (which provided brighter light) would work, but direct connection to housing triggers often failed (^[24]; ^[25]).

Community workarounds included using multi-core fiber optic cables for higher light transmission, ensuring precise alignment of trigger outputs with sensor ports, and daisy-chaining from a more sensitive strobe (^[26]).

Flooding

Some units experienced flooding of the strobe housing itself (not the battery compartment). At least one user had a flooded unit replaced under warranty with a new YS-D2J, though the process took nearly 4 months (^[27]).

On/Off Switch Failures

Unreliable magnetic on/off switches were reported, with Sea & Sea service departments sometimes attributing the issue to “water ingress into the magnetic on/off switch compartment” and refusing warranty coverage. Users disputed these claims, and at least one owner successfully repaired the switch by cleaning it (^[28]).

Service and Warranty Issues

Repair times were consistently reported as extremely long — typically 3-4 months — as units often had to be shipped to Japan for diagnosis. One user in Malaysia waited 6 months for resolution, during which the strobe sat with a Taiwan distributor without being forwarded to Japan. Sea & Sea Japan’s direct communication was difficult to establish; the user ultimately reached them through their Facebook page (^[29]). One retailer in Malaysia reported that “3 more units of YS D2 has been returned due to faulty issues” beyond the original complaint (^[30]).

Community Impact

The reliability problems significantly affected Sea & Sea’s strobe reputation. Forum members frequently advised prospective buyers to choose alternatives:

• “Sell both strobes and buy a pair of Inons, as practically all the strobe problems narrated here involve Sea and Sea strobes” (^[31])
• “The S&S black models have a not so good reliability reputation which is why the YS-D2J came out” (^[32])
• “No way to continue with Sea & Sea strobes, even if they gave them for free” (^[33])
• Users reported switching to Inon Z-330, Retra Flash, and other alternatives

Multiple users adopted the practice of traveling with three strobes as insurance against YS-D2 failures (^[34]).

TTL Compatibility and Accessories

TTL Converters

The YS-D2 was supported by several third-party TTL converter systems:

• UW Technics TTL Converter — Available from February 2016 for Nikon cameras, later expanded to Canon. Compatible with YS-D1, YS-D2, and Inon Z-240. Offered both optical and electrical TTL triggering. Priced at $430 when distributed by Nauticam USA (^[35]; ^[36]).
• UW Technics External TTL Controller — Announced January 2017, attached via M14 housing port. Compatible with all Nikon cameras and YS-D1, YS-D2, Z-240, YS-250, and DS-161 strobes (^[37]).
• TRT-Electronics Turtle TTL Trigger — Released November 2016, priced at €599. Supported Canon and Nikon cameras. Tested with YS-D1, YS-D2, YS-250, Ikelite DS series, and Inon Z-240 in both electrical and optical triggering modes (^[38]).
• UW Technics TTL Converter for Sea & Sea MDX Housings — Shipped May 2019, priced at $450. Designed for user installation into Sea & Sea MDX housings with both optical and electrical synchronization and on-camera strobe control (^[39]).

Note: One community member cautioned that using TTL converters with the YS-D2 could exacerbate the overheating/flash tube problem by enabling rapid-fire shooting that the strobe was not designed to sustain (^[40]).

Sea & Sea YS Optical Converter

Sea & Sea produced its own YS Optical Converter for Canon EOS R cameras in MDX housings, compatible with both YS-D1 and YS-D2 strobes, offering TTL and manual exposure control with a housing-mounted activation button. It shipped in April 2019 (^[41]).

Third-Party Accessories

• CM Diffusers Series II — Dome diffusers redesigned specifically for the YS-D1/D2, using a new frosted material for enhanced light transmission and improved edge fall-off. Priced at $75 each (February 2018) (^[42]).
• EZKnobs — CNC-machined aluminum extension knobs for cold-water diving, designed to fit over YS-D2 controls for easier operation with thick gloves. Launched on Kickstarter in September 2017 at $40/pair (^[43]).
• Marelux SOFT — Smart Optical Flash Tube snoot device, compatible with YS-D2 and YS-D3 among other strobes. Priced at $470 plus $80 mounting dock (March 2022) (^[44]).

Competitive Position

The YS-D2 competed primarily against the Inon Z-240 in the mid-range underwater strobe market. While the YS-D2 had a higher guide number (GN 32 vs. GN 24), this advantage largely disappeared when using diffusers to match the Z-240’s wider beam angle. Community members frequently noted the Inon’s superior reliability as the deciding factor (^[45]).

In Alex Mustard’s comparative strobe testing published in February 2017, measured guide numbers (from photos, ISO 100, in meters) with diffusers were: Inon Z-240: GN 16, Sea & Sea YS-250: GN 16, Ikelite DS161: GN 16, Sea & Sea D1: GN 18 (narrower beam). The YS-D2 was not separately tested but shared the D1’s flash tube design (^[46]).

The Retra Flash, announced in February 2017, was explicitly positioned as “a performance upgrade for photographers currently shooting INON or Sea & Sea D1/D2 etc strobes,” offering wider, more even light in a similar form factor with the same Sea & Sea sync cables and 4xAA batteries (^[47]).

Reviews

The YS-D2 was reviewed in UwP (Underwater Photography) Magazine:

• Issue 86 (September/October 2015) — Peter Rowlands reviewed the YS-D2 (^[48])
• Issue 87 (November/December 2015) — additional YS-D2 coverage (^[49])

Adam Hanlon used borrowed YS-D2 strobes (from Ryan Mack) during his Nikon D500 field review, alongside Inon Z-240 strobes (^[50]).

Successor: YS-D3 Lightning

The YS-D3 Lightning, which began shipping in April 2020, addressed several YS-D2 shortcomings. Key improvements included a higher guide number (GN 33), a target light “about 4 times brighter than YS-D2,” newly designed charging circuitry for faster continuous shooting (GN 16 with zero interval, GN 22 in 0.8 seconds), higher color temperature (5800°K vs. 5250°K), and an aspherical optical toroidal lens for more even light distribution. The YS-D3 was explicitly rated to 100m depth and shared the same YS base mount as the D1/D2 (^[51]).

Timeline

• 2015-07-02: Sea & Sea announces the YS-D2, priced at $719.95, shipping from July 15 (^[52])
• 2015-07-15: YS-D2 begins shipping (^[53])
• 2015-09: Peter Rowlands reviews the YS-D2 in UwP Magazine Issue 86 (^[54])
• 2015-11: Additional YS-D2 review coverage in UwP Magazine Issue 87 (^[55])
• 2016-01: First reliability complaints appear on Wetpixel forums — user reports both brand-new YS-D2 strobes failing at depth (^[56])
• 2016-02: UW Technics releases TTL converter compatible with YS-D2 (^[57])
• 2016-04: Additional flash tube explosion reports; user notes “3 more units” returned to Malaysian retailer (^[58])
• 2016-05: Nauticam USA begins offering UW Technics TTL converter, compatible with YS-D2, at $430 (^[59])
• 2016-11: TRT-Electronics Turtle TTL trigger released with YS-D2 compatibility (^[60])
• 2017-02: Alex Mustard’s strobe comparison test includes Sea & Sea D1/D2 class alongside competitors (^[61])
• 2017-03: User reports both YS-D2 flash tubes replaced in 7 months / 90 dives, recommends avoiding the strobe (^[62])
• 2017-06: Continued flash tube failure reports; units described as “a pile of powder” after 15 months (^[63])
• 2017-09: EZKnobs for YS-D2 launched on Kickstarter (^[64])
• 2017-10-03: Sea & Sea announces the YS-D2J (Japanese-manufactured version), priced at $689.95, explicitly responding to reliability reports (^[65])
• 2018-02: CM Diffusers releases redesigned Series II dome diffusers for YS-D1/D2 (^[66])
• 2019-04: Sea & Sea ships YS Optical Converter for Canon EOS R, compatible with YS-D2 (^[67])
• 2019-05: UW Technics ships TTL converter for Sea & Sea MDX housings, compatible with YS-D2 (^[68])
• 2020-04: Successor YS-D3 Lightning begins shipping, with significant improvements over YS-D2 (^[69])
• 2022-03: Marelux SOFT snoot device ships with YS-D2 compatibility (^[70])
• 2023: Users still reporting YS-D2 triggering and reliability issues; community commonly advises switching to alternatives (^[71]; ^[72])

Community Discussion

• ^[73] (18 replies) — Pre-release comparison discussion; early adopter reports on faster recycling and improved controls
• ^[74] (23 replies) — The primary reliability complaint thread, directly referenced in the YS-D2J announcement article. Covers circuit board failures, depth-related issues, flash tube explosions, and warranty struggles
• ^[75] (5 replies) — Buying advice for beginners; power considerations for compact cameras
• ^[76] (18 replies) — Competitive comparison; community generally favored Z-240 for reliability
• ^[77] (20 replies) — Extensive thread documenting flash tube and switch failures across multiple users and years (2017-2019)
• ^[78] (11 replies) — Sync/timing issues; Adam Hanlon notes “even with the YS-D2’s poor reputation” the symptoms likely indicate user configuration error
• ^[79] (8 replies) — 2023 thread; user ultimately returns YS-D2s and purchases YS-D3s
• ^[80] (7 replies) — Optical sensor sensitivity problems with Sony A1 housing
• ^[81] (36 replies) — Detailed troubleshooting of sync issues with UW Technics trigger and YS-D1 strobes, applicable to YS-D2

References

Wetpixel Live