之前听参加的国内FS700发布会的朋友说，现场技术透露FS700外录目前只能1080 50p 8Bit 422，高速只有28码流的AVCHD不能外录，外录慢速回放也是压缩后的8Bit 420。8秒的高速录制（记录单元为sony／ssd），需要等十几二十秒的缓冲，才能开始下一次录制。
正常情况下，当你用FS700拍摄超慢速时，摄影机缓冲慢速素材会在读取前先进入到一个内部缓冲区，然后记录AVCHD到内部存储卡中。摄影师Alister Chapman公布了一个消息。他在测试中发现，索尼FS700可以通过外部记录器记录超慢缓冲。

设置输出：
摄像机的输出可以在菜单中设置为25/30p或50/60p，如果设置为50/60p 需要3G HDSDI输出。因此，如果相机输出设置为25/30p需要1.5G SDI输出。结果是，如果你拍摄200帧输出25P，你最终将记录相当于100 fps  with a 180 degree shutter。
他说，一般的HD记录器都可以记录到1080p 25（或者1080p 30）。但要获得最优的外部高速记录，你需要设置FS700通过3G SDI 输出50/60p，那么你必须使用有3G SDI的外部记录仪。如果你记录50/60p然后在编辑时再减缓50％，最终你将得到全高清分辨率，且不会被再次压缩的200/240帧每秒的视频。
感觉被绕进去了，还是发出原文给大家看吧：
Great news. I was able to confirm yesterday that it is possible to record the super slow mo buffer stream from the Sony FS700 to an external recorder. When you shoot Super Slow Mo with the FS700 the camera buffers the slow motion footage into an internal frame buffer before reading this frame buffer out and encoding it to AVCHD to write to the internal compact flash card. The footage is read from the frame buffer at 50/60p depending on which country area the camera is set to.
Setting up the output.
The cameras output can be set in the menu to either 25/30p or 50/60p, if set to 50/60p the HDSDi output is 3G. In either case the buffering happens at 50/60p. So, if the camera output is set to 25/30p you only get every other frame of the buffer stream on the output Sdi at 1.5G. The end result of this is that if you shoot at 200 fps with the camera output at 25p you would end up with an external recording the equivalent of 100 fps with a 180 degree shutter.
Every external HD recorder that I know of can record this as it is nothing more than 1080p25 (or 1080p30). A very useful and a nice option. But to get the full benefit of external high speed recording you need to set the FS700 to output 50/60p over 3G SDi and then you must use an external recorder that has 3G SDi and can record at 1080 50/60p, something like the Convergent Design Gemini. Using a 50/60p external recorder you can then record every frame from the frame buffer. If you then take this 50/60p recording and slow it down by 50% in the edit suite you end up with full HD resolution, uncompressed 200/240 frames per second video. Very impressive indeed!
来源：http://www.xdcam-user.com/2012/06/uncompressed-slow-mo/