Sea&Sea are shipping their housing for the Sony a7 Mark III mirrorless camera. It is compatible with all Sea&Sea’s DX port series, optical viewfinders and S1 Optical Converter and features a Buoyancy Pocket that can accommodate an additional power pack to power the camera and helps to make the relatively small housing only 700 grams negative in the water.

From Sea&Sea(http://www.seaandsea.jp/products/digital_slr/mdxa7iii/)

Mirror Less / SLR Camera Housings MDX-series MDX-α7III

Features

Housing designed for ease of use and weight underwater Compatible with all the DX (NX) ports series. Larger diameter lenses can be easily removed through the increased housing port diameter to enable battery exchange in camera body without removing lens.

Sea&Sea engineers have designed a unique Buoyancy Pocket*, which can also accommodate accessories such as a mobile battery charger**, without compromising the overall size of the housing. The availability of an optional battery charger has addressed battery life of the camera and allows shooting for extended periods without concern of camera power loss.

The internal space also contributes to the reduction of the weight underwater. Combined with the lightweight camera body, we realized a phenomenal underwater weight of 700 grams***, eliminating the necessity to attach large floats.

*Approx 100×63×24(mm)
**Please note any and all restrictions by camera manufacturer when using 3rd party accessories. Please use these products at your own discretion.
***Housing configured with DX macro 87 Port and SL90M28G lens.

Compatible with optical converter S1

Compatible with Sea&Sea “optical 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 like other companies, but also performs TTL auto light control.
※ Sony original adapter “ADP - MAA” is required separately for connecting the camera and optical converter.

MDX-α7III 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.
• The camera’s diopter adjustment dial can be operated from outside the housing. This feature is useful when two or more people with different eyesight use the housing.
• 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 the housing, the upper part of the camera’s viewfinder cannot be viewed due to vignetting.
• Sync Cord 2-pin Connector enables the use of conventional hardwired Sync cable (Manual mode only).
• Equipped with two sacrificial zinc diodes (one on the front case and the other on the rear) to prevent electrolysis damage.
• Built-in leak sensor immediately alerts you to water ingress.
• Tripod screw mount is located on the center underside of the housing.
• Equipped with under guard to protect from scratches.

Specifications

MDX-α7III

Construction Body: corrosion-resistant aluminum alloy (machined)
Grip: corrosion-resistant die-cast aluminum alloy
Depth rating: 100m / 330ft
Dimensions (WxHxD) 328 x 188 x 131 mm / 12.9 x 7.4 x 5.2 inches
Weight Approx. 2,700g / 95oz (Housing only)

System Chart (current as of 2018.8.17): pdf