Use this 3.5" Extension Ring to increase the length of your Aquatica underwater DSLR housing's port, thus enabling the use of longer lenses, such as Canon's EF 17-40mm f/4L, 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, Such as Canon's EF 17-40mm f/4L, or Teleconverters

Related Questions and Answers

Q: 1. compatible with helios 44-2?

A: If the Helios 44-2 focus ring has a diameter between 49.5 to 51.5mm, then it would be compatible. Please note this is not the filter diameter, but the diameter of the focus ring. See these instructions on how to measure your lens to find the correct gear size here: https://bhpho.to/3QsFlEO.

Q: 2. Which ring will fit a sigma 18-35mm 1.8?

A: No it will not, the Tilta Seamless Focus Gear Ring (46.5 to 48.5mm) is not large enough for the Sigma 18-35mm 1.8 ART lens. Instead you will need the Tilta Seamless Focus Gear Ring (78 to 80mm) which is B&H number TITAFGR7880. Here is the link to the product - https://bhpho.to/38pZeZT

Q: 3. 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: 4. My lens' focus ring diameter is 61.75mm. Should I get the 59-61mm or 62.5-64.5mm ring?

A: we recommend going with the smaller size.

Q: 5. Which size ring for Sony 50 1.2; Sony 35 1.8; Sony 35 1.4?

A: Please use the following ruler to measure your lenses for the correct Tilta Seamless Focus Gear Ring size. Ruler: https://bit.ly/49uzp62

Q: 6. Will this gear be the same pitch as the gear on a Rs2 focus motor setup so they fit together?

A: yes it is.

Q: 7. What is the MOD pitch of this? I know it's not 0.8 because it doesn't work with my 0.8 nucleus m gear

A: The Tilta FR-T03 gear is for MOD 0.8. pitch module TiLTA Lens Gear Rings Specifications:• Pitch Module : 0.8 - 140 • Maximum Diameter : 105mm

Q: 8. what size do I need for a Xeen lens?

A: Rokinon XEEN Cine lens are built with gears on the focusing ring.

Q: 9. Will this fit the Sigma Art 50-100mm 1.8?

A: The Tilta DSLR Lens Follow Focus Adapter is a universal lens gear that would support many lens models including the model you were working with.

Q: 10. would this fit Tamron SP 24-70mm? The Nucleus-M or my shape FF slip sometimes on the Tamron gears.

A: The Tilta DSLR Lens Follow Focus Adapter will fit around the Tamron SP 24-70mm f/2.8 Di VC USD G2 Lens for Canon EF, which has a diameter of 88.4mm.