This latest bit I've started using myself and selling to others has proved to be quite useful. It is not meant ONLY for the Alexa- it is used with every camera body and configuration out there.
Howeer, the most recent iteration of Longplate build involves an Arri Alexa.
Here's the video that Chris Fawcett did last year showing the neat trick of using just a long plate and the threaded washer that Tiffen makes to eliminate ALL other plates when building up an Alexa.
Not only can you grab the bottom of the body at two points, but the Longplate allows you to also mount Transmitters or other accessories behind the body and/or follow focus rods and brackets up beneath the lens, or a ringlight. Many options, limited only by the Operator's imagination.
The Longplate fits the following stages: Steadicam, GPI/PRO, XCS, Sachtler and Betz.
Contact me by email with any questions not addressed on the Facebook page. The production run was of 60, 12 are already sold and in use. The Longplate is $ 300.00 and comes with custom cut washers to allow the use of 1/4-20 machine screws as well as 3/8-16 machine screws.
Best to all,
Peter Abraham, S.O.C.