MDX-α1 U

for Sony α1

This image was captured in the waters off Miyakejima, a volcanic island located south of Tokyo, Japan, where wild dolphins are frequently encountered.

For this shot, I used a Sony α1 paired with the SEL14F18GM lens, housed in the SEA&SEA MDX-α1U with the Optical Dome Port II 230 and DX Extension Ring 30L.

The dolphins around Miyakejima often travel along dramatic underwater landscapes formed by ancient volcanic activity. Anticipating their route, I performed a duck dive to approximately 10 meters (33 feet) and waited near a lava rock formation. Moments later, a pod of dolphins swam directly over the volcanic reef, creating the opportunity for this image. My goal was to capture both the rugged beauty of Miyakejima’s volcanic seascape and the freedom and energy of the dolphins in a single frame.

As with my whale photography, I chose to work exclusively with available light and did not use strobes. The weather was overcast, resulting in limited light penetration underwater, so I set the camera to ISO 800. To freeze the dolphins’ fast and unpredictable movements, I used a shutter speed of 1/200 second.

The ultra-wide angle of the SEL14F18GM allowed me to include both the dynamic movement of the dolphin pod and the unique volcanic topography of Miyakejima. The excellent ergonomics and responsiveness of the MDX-α1U housing enabled me to react quickly to the dolphins’ unpredictable behavior and capture this fleeting moment with confidence.

View more photos

Product No.	Color	Strobe Sync
07144	Black	Electorical
07145	Black	Optical Manual
07146	Black	Optical TTL
07147	Silver	Electorical
07148	Silver	Optical Manual
07149	Silver	Optical TTL

Features

01. Universal design for the future The back panel is designed to be large.

The back acrylic panel is more than twice as large as before to improve visibility of the monitor and reduce the underwater weight.
Furthermore, it is a sustainable design that can be used with new cameras in the future with minimal parts replacement.

02. Newly designed optical fiber cable cover.

Newly designed fiber-optic cable cover included. Prevents optical cable terminals from falling out and smartly protects light-emitting panels and cable terminals. Includes a strap to prevent loss of the cover.

03. Leak Alarm Unit as standard equipment

The Leak Alarm Unit, which was previously available as an option, is now included as standard equipment.
It is effective not only for early detection of underwater flooding accidents, but also for protection of equipment by checking its waterproof performance before entry.
CR2032 lithium battery included.

Product No.44135 Leak Alarm Unit Product Page.

Download the Mode Change Procedure Manual

Here is a guide to the different modes of the leak alarm unit and the setup procedure.

Mode Change Procedure Manual

04. Strobe Synchro System

Three optional strobe connection methods are available.

1.Optical TTL connection
[Product No.50151] Optical YS Converter S2

Compatible with SEA&SEA “Optical YS Converter S1” which converts the strobe light emission signal of the camera to LED light and synchronizes with the SEA&SEA YS strobe. It is a high-performance converter that does not just emit simple light-emitting signals, but also performs TTL auto light control.

* The Sony original adapter "ADP-MAA" is no longer required for connection to the camera.

Optical TTL connection

2.Optical manual connection
[Product No.50146] Manual flash trigger

For those who do not need TTL photography, the fiber-optic cable connection enables manual firing of the YS strobe.

Optical manual connection

3.Electrical connection
[Product No.50147] Strobe connector/N
[Product No.50122] Optional Sync Cord 2-pin Connector

YS strobes can be electrically connected with a sync cord.

Electrical connection

05. Full range of standard equipment

Grip Plus made of silicone material.
Robust yet secure fit to hold the housing in place.
Lighting can be deployed as desired from the SA8 fixed ball base.
Pre-equipped with lanyard hooks for convenient transportation.

06. Focus Point Movement Settings

To perform "focus point operation" during shooting, please make a custom setting for the focus point in the dial customization of the camera in advance. The focus point can be moved by operating the front/rear dial.

The following is a guide to the setup procedure for assigning the focus point operation to the front and rear dials.

Gallery

Photo： KIM Suseong

Camera :

SONY α1

Lens :

SONY SEL14F18GM

F :

6.3

SS :

1/125

ISO :

640

Photo： KIM Suseong

Camera :

SONY α1

Lens :

SONY SEL14F18GM

F :

SS :

1/125

ISO :

400

Photo： KIM Suseong

Camera :

SONY α1

Lens :

SONY SEL14F18GM

F :

SS :

1/800

ISO :

800

Photo： KIM Suseong

Camera :

SONY α1

Lens :

SONY SEL14F18GM

F :

SS :

1/250

ISO :

500

Other Features

The Port Lock prevents the port from turning or loosening and the Port Lock lever is specifically located to avoid being unlocked accidentally.
The housing is equipped with a lens-lock release button which makes it possible to change lenses easily, without opening the housing.
Pulling out the Focus/Zoom Dial gives sufficient room inside the housing to easily accommodate larger diameter lenses.
All controls have luminescence stickers which glow in dark environment.
Equipped with the Optical Viewfinder 0.5x as standard. Other optional viewfinders such as the VF180 1.2x, VF45 1.2x and Optical Viewfinder 0.66x, 0.8x can be used.
※Some vignetting occurs.When the VF180 1.2x is mounted on housing, the uper part of the camera's viewfinder cannot be viewed due to vignetting.
Equipped with two sacrificial zinc diodes (one on the front case and the other on the rear) to prevent electrolysis damage.
Tripod screw mount is located on the centre underside of the housing.
Equipped with under guard to protect from scrach.

Specifications

[Construction]
Body: corrosion-resistant aluminum alloy (machined)
Grip: corrosion-resistant die-cast aluminum alloy
[Depth rating] 100m / 330ft
[Dimensions (WxHxD)] 330 x 169 x 137 mm / 12.9 x 6.6 x 5.4 inches
[Weight] Approx. 2,900g / 102.3oz (Housing only)
［Set Item]
Silicone grease, O-ring remover, Hex wrench (6mm / for grip dismounting), Hex wrench (4mm / for Lanyard bolt), Hex wrench (2mm), O-ring maintenance manual, Instruction manual (this manual), CR2032 lithium battery (for leak alarm unit), Leak alarm unit manual pump

Attached accessories to the product
Housing body cap, Fiber-optic cable cover
System Chart