Meike announced a 6-11mm f/3.5 fisheye lens for both the Canon EF and Nikon F mount. This manual focus lens has the same 180-degree field of view as the Canon EF 8-15mm f/4L fisheye at 6mm.
The 6-11mm f/3.5 fisheye also offers a 180-degree field of view for APS-C and Micro 4/3's shooters.
Meike 6-11mm f/3.5 Fisheye Zoom Specifications:
- Lens Type: Fisheye
- Max Aperture: f/3.5
- Minimum focus distance: 150mm at 6mm, 250mm at 11mm
- Focal length: 6-11mm
- Lens structure: 8 groups / 11 elements
- Size: 64mm x 94mm
- Weight: 541g
Unfortunately it's not full-frame but designed for APS-C sensor. Although it'd presumably mount on FF bodies, how well it'd work on them is uncertain.
I'm already using a M43 Samyang Fisheye with EF-M mount conversion for that purpose, but the lens is not good when it comes to flares (which outdoors is always the case with 360 panos).