Opteka 6.5mm f/3.5 CS fisheye

I like fisheyes and have a small collection of them. The Samyang 8mm offerings have long appealed to me, but I really didn't want to spend $250 on another fisheye. Well, then I found the Opteka-branded 6.5mm (really 8mm) f/3.5 CS (really CSII, since it has the removable hood) available new for $150... and couldn't resist.

My money was well spent. It is truly excellent, especially stopped down a couple of stops. It provides enough resolution for 24MP APS-C, little CA, and usually no more than one modest patch of flare. Here is an out-of-camera unprocessed JPEG from it on my NEX-7 in Fiji as both scaled to 900x600 and a 1:1 900x600 crop:

Opteka 6.5mm f/3.5 around f/11 on NEX-7

Opteka 6.5mm f/3.5 around f/11 on NEX-7, 1:1 crop

I got this in Nikon mount so that I could not only use it on my NEX-5, NEX-7, A7, and A7II, but so I also could use it with an F->FD adapter and my FD Lens Turbo (LT) focal reducer behind it. You see, on FF (e.g., my A7II) using the LT with the (somewhat fragile mounting) removable hood off, it becomes an unclipped circular fisheye. The unprocessed JPEG result looks like this shot inside the Green Dragon in Hobbiton:

Opteka 6.5mm f/3.5 on A7II using Lens Turbo

Oddly, the projection of this lens seems far less distorting than most fisheyes, so the circular format has less appeal as a final image format. I think I'd only use this trick to make two-shot 360-degree panoramas.

One last note: the Nikon F mount version of this lens has a mount that is a little loose on Nikon adapters. I needed to shim it by the thickness of one piece of Scotch tape. It also is really critical that any adapter be precisely the right thickness, because the movement for the entire focus range of this lens is tiny -- probably about 1mm in total.