Fish lens alternative

[orenbvip]

I want to use a fisheye lens with a dome port (precision) and I find the Panasonic to be a bit pricey at $600+. I have seen a few alternatives such as this one:

Amazon.com: Rokinon FE75MFT-B 7.5mm F3.5 UMC Fisheye Lens for Micro Four Thirds (Olympus PEN and Panasonic): ROKINON: Camera & Photo

just wanted to know if anyone has tried or can recommend any. Or do I just bite the bullet and shell out.

 

[Yoav Lavi]

To my understanding, this lens has no electronics, which means manual focus and aperture, which will be difficult to change underwater.