I've been buying and testing lots of NEX adapters for many different lens mounts (PL, Canon EOS, Nikon F, Pentax K, Canon FD.) What I've noticed is that all of these adapters will work on the consumer DSLR NEX cameras but some won't fit on the FS700. Some won't let the locking pin drop into the slot and others won't rotate at all.
What's really interesting is that the MTF PL adapter fits the FS700 perfectly, but the 16x9 one won't lock in place (I've tried three different FS700 bodies.) However, the 16x9 version fits fine on the FS100.
I assume this means the tolerance is tighter with the FS700 NEX mount, but I was wondering if anyone else has had similar issues?

Here's a list of adapters I've tested.

16x9 PL (http://16x9inc.com/shop/cart.php?m=product_detail&p=666) - FS100 yes. Won't lock pin into FS700 but otherwise fits.
MTF PL (http://www.mtfservices.com/home.html?page=shop.product_details&flypage=flypage.tpl&product_id=102&category_id=2) - Works well on all mounts. Solid construction.
Redwood PL - (http://www.ebay.com/itm/Arri-Arriflex-PL-Sony-E-mount-NEX-Adapter-VG10-NEX3-NEX5-NEX7-FS100-etc-/181134302457?pt=US_Lens_Adapters_Mounts_Tubes&hash=item2a2c721cf9)Works well (and is cheap) but the PL lock ring is threaded which can be confusing. There's no threaded 1/4"-20 hole for rail support.
Fotga Pentax K (http://www.ebay.com/itm/Fotga-Pentax-PK-Lens-to-Sony-NEX-E-Mount-NEX5-NEX7-NEX-VG10-NEX-5N-NEXC3-Adapter-/270853638671?pt=US_Lens_Adapters_Mounts_Tubes&hash=item3f10228a0f) - works well
Fotga Canon FD (http://www.ebay.com/itm/Fotga-Canon-FD-Lens-to-Sony-E-Mount-NEX3-NEX5-NEX7-NEX-VG10-NEX-5N-NEXC3-Adapter-/270848906468?pt=US_Lens_Adapters_Mounts_Tubes&hash=item3f0fda54e4) - won't rotate at all and cannot be mounted on FS700
Generic EOS (http://www.ebay.com/itm/Adapter-Canon-EOS-EF-lens-Sony-NEX-3-NEX-5-E-mount-/350571933104?pt=US_Lens_Adapters_Mounts_Tubes&hash=item519fb72db0) - Fits well but will only work properly with manual iris lenses
Roxsen Nikon F with tilt (http://www.ebay.com/itm/Tilt-Nikon-F-AI-S-lens-Sony-E-Mount-Adapter-NEX-5-C3-NEX-7-NEX-VG10-NEX-5N-/150629794792?hash=item23123c43e8) - works well with my old Nikon D lenses. Will not work with G lenses. Tilt is a nice feature but the decal with the numbers keeps popping up.
Roxsen "Zhongyi" Canon FD "Lens Turbo" (http://www.ebay.com/itm/Focal-Reducer-Speed-Booster-Adapter-Canon-FD-mount-lens-Sony-NEX-5R-3N-6-7-5-/400488753177?pt=US_Lens_Adapters_Mounts_Tubes&hash=item5d3efd6819) - Similar design to a Speed Booster but won't rotate at all and cannot be mounted on FS700.

Please note that I do not necessarily endorse any of the eBay sellers and the links are only provided as image reference. I can't even remember specifically which ones I purchased from, I just did a quick search for each product and used the first link I found.

Tim ~

Haven't tried any PLs or adapters on NEX still cameras but I have been testing out the Photodiox Pro, the Photga and the Roxen 'Zhongyi' lens turbo on an FS700, with Minolta Rokkor MD mount primes and zooms. Primarily to find fixed aperture parfocal zooms for interviews. In all cases with the above adapters I have found the NEX side of the adapters fit the FS700 well with minimal movement once locked into place. No undue pressure required to get them on or off. Re the MD mount side the Roxen and the Photga are spot on but the Photodiox adapter is pretty tight fit with some of the lenses. Stiffer rotational force than I feel happy with. It also has the worst lens locking mechanism of all of them.

A major issue I have I have found with all these mounts is that they are ALL too short. Being short guarantees achieving infinity focus but creates major issues when used with known parfocal zooms. In all cases I have had to shim each adapter with varying thickness shims to get infinity at the stops and have 100% focus tracking throughout the full range of the zooms.

If interested a quick test of the zooms after shimming the mounts can be seen here:

Sony FS700 Parfocal lens tests x 3 with and without ' speed booster' - 1080-50p down to 720-25p 10.June.13 on Vimeo

Chris Young
CYV Productions
Sydney