Sensors larger than Super 35mm have become the norm for lots of uses, and in response to that, Tokina has introduced two different 1.6x expanders that increase the image circle for full-frame cameras. There will be two versions of this 1.6x expander, a PL to PL and a PL to Sony E-Mount.
These sorts of adapters are perfect for those who have invested quite a bit of cash in lenses, or for those occasional full-frame shoots. They are also handy if you’re adding a full-frame 4K camera — like an a7S II — as a B-cam to complement something like an FS7 and you’ve already got some PL lenses. The expander (and others like it) will be especially useful for those wanting to put Super 35mm glass on sensors like the WEAPON 8K, which has a diagonal over 46mm.
Unlike Speed Boosters that reduce the image circle for increased brightness and clarity, optical solutions for increasing the image circle are usually going to result in slightly worse performance overall — though this greatly depends on the adapter and how you’re using it. You’re also going to get a bit of light loss — in this case 1.36 stops. Tokina recommends that you use it with lenses that have a maximum aperture of T2.0 or larger, and that you stop down the lens to at least a T2.8. Stopping down any lens will usually lead to better sharpness, and it becomes especially important when you’re introducing other variables like a focal expander.
You can see the difference between the expander on Full-Frame vs. APS-C:
The 1.6x adapters will be available in November, priced at around $2,000.