How to record 4K from a NEX-FS700

Hi all.

First of all, this is my first article in English in this little corner, so I do apologize for the likely spelling and grammar mistakes I will surely commit. I hope that “the importance lays on the content” is really applied here. Also, bear in mind that I only work for Sony, but there is no revising from the company, so this is just and only my PERSONAL blog, related to product.

As you may know through other channels (YouTube, Twitter, presential presentations, fairs…), I work as Product Specialist for Sony Professional Solutions Europe. My colleagues and I try to provide pre-sales technical knowledge about the products in our division; in my case, camcorders.

So, one of our star products is NEX-FS700. As you may know, it’s a Super35 mm CMOS camcorder that can output 4K RAW signal, can record super slow-motion bursts (up to 240 fps in FullHD sensor scanning, and up to 960 scanning about 20% of the horizontal lines), and is compatible almost with any lens system thanks to its E-mount system.

One of the most asked questions is about 4K: when announced and released, it was told to be a 4K-ready camcorder. About 1 year later, we unveiled how we could do that: via a hardware upgrade, that would allow us to output RAW signal through its 3G-SDI interface.

Wait a moment… 4K, RAW, and SDI? What??? Yes; as you know, for a 4K signal, a HDMI 2.0 connection can be used or, on a professional environment, 4 3G-SDI cables are typically needed. So, where’s the trick? Actually, what we are doing there is compressing the signal, with a very low loss (or even lossless; I would need to review) algorithm. So, no standard communication, no baseband output (for instance, on Alpha 7s, the QFHD signal is outputted in baseband format, so any device that can “talk” that language will be able to display or record the signal).

As I was telling, we are using and algorithm, and it was originally designed for working on an AXS-R5-based recording solution. AXS-R5 is a recorder that was originally designed to be attached directly on the rear part of F5 and F55, and records signal over AXS memory cards. Such a high-level system needed a high-level algorithm to work with, in the case of FS700. So, we apply that algorithm to its output, we transmit that “bitstream data” (not “video stream”, actually), and on the other side it needs to be decoded. That is the first function for HXR-IFR5, the interface that we need to insert between the SDI cable and AXS-R5.

The second function that IFR5 does is to adapt physically R5: as told before, AXS-R5 was designed to be attached to F5/F55, so we need to provide that physical interface and, obviously, its multipin connection. And its third mission is to have a control panel over the recorder, in case we need to operate R5 directly (for instance, playback function over R5 cannot be commanded from FS700 – and bear in mind that R5’s output in that case is downconverted FullHD, not 4K).

HXR-IFR5 NEX-FS700 monitoring

[These slides are extracted from the presentation we used either when that option (v3.0) was announced), or at the FS700’s announcement time]

HXR-IFR5 with AXS-R5

Finally, as the only connection between FS700 and IFR5 is a single SDI cable (it can be really long, about 70 m, so nice for underwater shooting, cranes, etc, in which we don’t want to have a bulky and heavy camera head, and the rec system can be put in another location), there is no power, so a battery or a DC power feed needs to be used on the recording “kit”.

Ok, now it’s clear how it works, but… price? Well, we can say that, more or less, the price for the recording part (IFR5, R5, BP-FL75 olivine battery, AXS memory and card reader) can be comparable to the one of the camcorder itself. Nice if you already work with F5/F55, or your rental house have those camcorder models, but for a freelance user that only uses FS700, it can be really costy.

So, there is -at least, so far- an alternative solution to AXS-R5. I told that the algorithm we were using for outputting RAW signal is Sony property. The only company (as of October 2014, at least) that has got access to it is Convergent Design, and their Odyssey7Q recorder can be used not only as a decoder and recorder, but also as a monitor due to its OLED screen.

RAW output can be recorded in 12-bit depth DNG files. Also, for 4K, it can de-Bayer the 4K RAW signal flow from the SDI interface, downconverted into HD, and then recorded in Apple ProRes 422 (HQ) format. It has been announced that in a near future, 4K ProRes will be also available.

Seems nice, but… what about the price in this case? That is one of the strong points: as of October 2014, Odyssey7Q is announced for about 1421 € (on their website it is expressed in US dollars, and not with or without VAT), and the FS700 upgrade is priced about 630 €. So, a solution that costs about 2000 €.

You can find detailed information about Odyssey7Q here:

and about its FS700 upgrade here:

So, from my PERSONAL point of view, please bear in mind what you need, the format you are likely to work with, and then make your choice. Also, as a note, and because there were also some comments about it, Convergent Design is NOT Sony-owned company. It’s just a third party high quality recorder manufacturer, as Atomos, Focus, Cinedeck… can be. Or as the multiple E-mount adaptors (to EF, to PL, to… almost every lens system) manufacturers: Metabones, MTF, Novoflex, Birger… they are not owned by Sony, also.

E-mount adaptors

Finally, let me thank you for reading this -probably boring- article, but I think that sometimes it is useful that a Sony guy can tell you this kind of information as it is, without any official marketing tool involved between you and us.

Thank you very much indeed, and, again, sorry for my English. 🙂

PS: I will try to review this article and, in case there is anything to correct (probably), I will do, but preferred to provide it to you all asap.


2 pensamientos en “How to record 4K from a NEX-FS700

  1. H Hugo Montes

    Hola Alvaro.
    Tengo una Sony FS 700
    Me acabo de comprar el Blackmagic Video assist 4k.
    Se supone que puedo grabar 4k pero no encuentro ninguna opciòn en la càmara para ello salvo la de 4k RAW, pero el Blackmagic video assist solo recibe plain 4k (No raw).
    En què me estoy equivocando? O la FS700 sòlo bota 4k en Raw??
    Hugo Montes

    Me gusta

    1. Alvaro Ortiz Autor de la entrada

      Hola, Hugo.

      La FS700, al igual que la FS5, saca la señal en RAW, pero en un FLUJO DE DATOS. Es decir, convierte la señal 4K de vídeo en banda base, y la codifica. Por eso al otro lado del cable BNC se necesita algo que “decodifique” dicho flujo de datos.

      Los dispositivos que pueden hacer eso son el HXR-IFR5 de Sony, para posteriormente grabar el material en RAW en el AXS-R5, y algunos grabadores de las marcas Convergent Design y Atomos.

      Pero ten en cuenta que el vídeo no va en banda base; entre otras cosas, porque ese interfaz es 3G-SDI, y el formato que permite es, como máximo, 1080/50p ó 60p, pero no 4K; por eso se codifica, convirtiendo la señal a datos.

      Un atento saludo, y espero no haber liado más 🙂

      Me gusta



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