Use this 2.9" Extension Ring to increase the length of your Aquatica underwater DSLR housing's port, thus enabling the use of longer lenses or teleconverters. The ring features a manual focus knob, which is compatible with a required focus gear. For complete compatibility information, please click on the links below to view the port charts.

In addition to adding length, the ring is designed to allow for positioning of the front element of your lens as close as possible to the interior of the port, in order to minimize distortion for better image quality. See the Dimensions Chart to learn how to measure properly for an extension ring.

A stainless-steel locking mechanism ensures a reliable connection between the ring and the port, while your camera housing's own lock connects the ring securely to the housing. The extension ring is crafted from a 6061 T6 aluminum alloy, which has been anodized for excellent resistance to corrosion. It features a depth rating of 295'.

Port charts:
Canon Type 1
Canon Type 2
Canon Type 4
Nikon Type 1
Nikon Type 2
Nikon Type 3
Nikon Type 4
Sony Type 4

Allows for Use of Longer Lenses or Teleconverters

Related Questions and Answers

Q: 1. Does this come with the MPR-C flange? When RRS sell it on their own site, it doesn't come with it, you have to purchase it as an additional $5 item. Your description suggests it comes with it?

A: Yes, MPR-C flange is included with the Really Right Stuff 2.9 Multi-Purpose Rail (1/4 -20).

Q: 2. Is the dome Acrylic or Polycarbonate or something else?

A: The Dotworkz 4K Optically Pure Vandal Tough Clear Lens for D-Series Camera Housings is made from a hardened nylon material and polycarbonate.

Q: 3. While using this extension cable will I lose power? If so, how much? Thank you!

A: You will lose less than 5 % of power

Q: 4. Is it a wet lens?

A: The Backscatter M52 Wide-Angle Air Lens for Olympus PT Series Underwater Housings is a wet lens that has 52mm filter threads. This lens is perfect for the Olympus TG series cameras in the Olympus housing.

Q: 5. Does it works with Panasonic Lumix Gh5-2 and G9 Cameras?

A: The Venus Optics Laowa Zero-D S35 7.5mm T/2.9 Cine Lens (FUJI X, Feet/Meters) is not compatible with MFT-mount cameras.

Q: 6. Is any one using the 2.9 version of this as a lens foot plate on a Nikon AF-S NIKKOR 70-200mm f/2.8E FL ED VR Lens? If so, do you recommend it?

A: For that lens I have been using for years the RRS replacement foot which is great. I have used this style of plate for other lenses which do not have a specific Foot replacement. It works but is not as nice as if it was a foot replacement.

Q: 7. Will this work with the Blackmagic Ursa Broadcast Camera?

A: Yes, this also has a B4 mount.

Q: 8. The original M52 from backscatter comes with fiber optic cable adapter. Is it included in the box?

A: Yes, the Backscatter M52 Wide-Angle Air Lens for Olympus PT Series Underwater Housings comes with the Fiber Optic Cable Adapter.

Q: 9. Can you mount filters on the front end of the lens?

A: No you cannot.

Q: 10. What are some compatible tripod supports for this lens?

A: This is a very specialized product that will require you to talk with an expert directly before choosing the proper gear to go along with it. In most cases people would use a lens like this on a Pedestal System, B&H # SAS25S. So that we may best assist you, please email us at provideo@bhphoto.com.