Review: Sony’s HDR CX900 HD camcorder

Sony’s HDR-CX900 camcorder is an unusual beast. It’s physically quite large – this is no pocketable take-on-holiday camcorder. The lower-end brother of the much talked-about FDR-AX100 which shoots 4K UltraHD video, the CX900 is identical except for lacking that 4K mode; its highest- quality mode is standard HD albeit at a 50 Mbps data rate saved as XAVC-S files (essentially just like traditional AVCHD / h.264 but with a greater data rate for better detail in the images)

Apart from that headline feature, the camcorder also boasts an unusually large, 1-inch, image sensor with 20 megapixel resolution for still images and, unusually for Sony, plenty of manual controls using physical dials and buttons as well as on-screen options.

Sony CX900 from side
Sony CX900 from side

Let there be light
So let’s start with that sensor. Most consumer camcorders have sensors of between 1/6″ and 1/3″ but this one’s got a biggie, a full one incher. In theory this means both that it will be good in low light situations (bigger sensor means a greater area for any light to fall on so better sensitivity) and should be capable of providing a shallow depth of field when required, to get those “blurred background” looks.

In low light, the camcorder’s pretty good amongst its peers but the lens opens only to f2.8 which is slightly slow for a camcorder and ramps down to f4 by approximately two-thirds of the way through the zoom range. Nonetheless, we measured – by eye – the CX900 as having slightly better sensitivity at f2.8 than the Canon HF-G30 at its widest iris of f1.8 and both beat the Panasonic x920 even though it goes slightly faster than f1.7.

When added, gain on the CX900 is relatively clean too, certainly more so than the x920 and a degree better than the HF-G30. All in all then, a good performance. Just beware that, in auto mode, the CX900 delights in adding gain and speeding up the shutter in order to counteract low light, the latter resulting (if you’re not careful) in staccato video instead of fluid motion.

Steady on
The 20 megapixels on the sensor make for detailed still images and provide the camcorder with plenty of working space for a stabilisation function when videoing. Unfortunately the latter leaves much to be desired. Stabilisation is only acceptable at best when in “Standard” mode and though it is substantially better when switched to “Active” mode, this comes at the expense of image quality since the camcorder automatically activates its “Clear Image Zoom” when Active stabilisation is chosen.

Despite its name, we can see a distinct softening of the image when Clear Image Zoom is on, and though it generates what is effectively a 24x zoom compared to the standard 12x optical, the quality hit is palpable, even if you zoom back to the equivalent of the 12x. Here are our video tests, demonstrating the issue:

Three levels of ND (Neutral Density) filter plus none at all are available, selected either manually via a tiny, rather fiddly, switch on the back near the viewfinder or by the camcorder itself when the ND Auto/Manual switch is flipped to Auto. Oddly though, it would only ever switch on ND1 for us even when pointed at the sky with the lens – also on auto – stopped down to f11. We had to manually switch in ND2 or 3. No idea why, unless why have a faulty camcorder.

And… Action!
Film makers rejoice! This camcorder, yes even the UK version, can be switched to a 24p mode though this does require you to a) reboot it and b) reformat your memory card. Actually it’s not 24p, it’s the US 23.976 fps standard but given that UK camcorders usually only offer 25p due to that being our native frame rate and therefore apparently considered “close enough” by camcorder vendors, this genuine 24p film-style ability is to be welcomed. Of course, that’s assuming you like the film look which inherently has a jittery feel to the footage due to the low, progressive, frame rate. Here’s our test of that as well:

For more conventional video shooting, the HDR-CX900 offers traditional AVCHD up to 28 Mbps / 50p (60p in the NTSC countries eg the USA) plus a rather unusual 50 Mbps recording mode with files stored in Sony’s XAVC-S format. Essentially this is just a faster bitrate version of AVCHD / h.264 so most editing software should be able to cope; we use Sony’s own Vegas Pro 12 which as you’d expect takes it in its stride.

Where’s the devil? In the detail.
Pictures are decent enough, very detailed and crisp although when left on Auto exposure – not that we ever recommend this – the camcorder definitely seems to have a tendency to over-expose we think; take a look at the sky in the video below and notice how the clouds are completely blown out. Yes this was an image of heavy contrast, from the shadows under the trees to the highlights in the sky and the grass, but we think it ought to come down a notch.

Alas there’s no way of adjusting the default auto exposure – the exposure compensation function available via the dial or on-screen menus does dial it down but then locks the exposure rather than simply providing an offset for the auto to then work with as it varies according to the scene.

Quiet on set
Sound is provided by a 5.1-capable built-in microphone in the usual place just behind the lens ring and therefore potentially liable to pick up handling noise (note also that in top-quality XAVC-S filming, this is set to stereo only). It’s not a bad mic, relatively speaking, and offers the usual choice of low-cut filter to help to eliminate wind noise.

Sony CX900
Sony CX900

It also has an unusual “camera-operator-removal” function (!) that attempts to reduce sound coming from behind the camcorder, ie from the person doing the filming, and focus on sound coming from in front. In practice this had a slightly disconcerting effect on the recorded sound and little noticeable actual reduction of the unwanted operator noise.

As usual, better sound can be achieved by adding an external mic via the included 3.5mm unbalanced jack (a headphone socket is also given for proper monitoring). There’s also a hot shoe on top of the camcorder to which Sony’s own XLR audio unit can be connected which interfaces directly with the camcorder via tiny electrical pins; Sony’s design of this shoe makes adding normal accessories impossible without the help of an adapter which is really rather irritating.

Wresting control
In terms of manual operation, there’s a nice lens ring at the front which can be switched to operate the zoom if that’s your preference; a focus assist button, rather awkwardly placed on the right hand side of the lens (but out of range of your right hand), enables two levels of on-screen (not recorded) zoom to help you get precise focus and by touching on the flip-out LCD screen you can even select which part of the image gets zoomed if you wish.

Focus peaking (coloured highlights around high-contrasting sharp areas) can also be switched on with a choice of colours and sensitivity. You can touch the screen to select an area for autofocus or there’s face recognition to automatically focus (and expose, if required) on human beings. And you can select a non-face object for the camcorder to track and maintain focus on though in our tests this was dependent on the object being distinctive in the image and not moving too fast.

Sony CX900 from back
Sony CX900 from back

For exposure, there’s a seemingly slightly complicated system until you get used to it by which the camcorder can be in full auto including the ND filters (though see our note about this, above); or various combinations of partial auto either using the screen or the control dial.

For example, you can operate the NDs yourself or have the camcorder do it; you can fix the shutter speed and let the camcorder vary iris and gain; or in fact you can fix any combination of shutter / iris / gain and let the camcorder work whichever ones you’ve left in auto. You can set a limit to the amount of auto gain if you dislike it, though see our “low light” note above; it’s not too bad.

Finally there’s a semi-automatic “E” mode where your use of the control dial will adjust Exposure based first on opening the Iris then upping the gain when the iris can open no more.

To assist with exposure, zebra bars can be invoked at a range from 70 to “over 100” in steps of 5 percent. Equally, in auto mode, you can expose by touching the part of the screen you want set and the camcorder will adjust, though we found it a bit crude perhaps due to our podgy fingers.

As an eagle-eyed reader of this review has already noted – see the top comment below – there is no apparent LANC control socket on the camcorder. However, it is our understanding – though we stress we have not tested this – that external control can be achieved through the tiny, USB-like connector labelled the “Multi A/V” socket, on the side of the camcorder. In order to connect it to Sony’s range of remote zoom controls, you need to purchase an additional adapter cable from Sony, badged the “VMC-AVM1″ – it costs £20 GBP on the Sony UK site. There’s actually a video on YouTube (not one of ours) which demonstrates the cable on an AX100:

Shots Miscellany
There’s wifi control using an App for your tablet or mobile phone; switching this on turns the camcorder into a WiFi hotspot which your mobile then connects to and the App gains control. Unfortunately this seems to be limited to start/stop recording and zoom control; the rest of the camera appears to operate in auto mode.

You can also download mp4 files recorded by the camcorder (at 3Mbps, 720p only) to the phone so as to forward on to social networks and the like. Weirdly, you can’t copy off the good quality AVCHD or XAVC-S footage.

The touch screen is decently large and can be kept cluttered with useful status information or entirely clear with the press of a button, which is good. It insists on telling you the lens cap is on every time you start up (if indeed it is) which became annoying very fast. We are aware of the need to remove the lens cap, Sony – it’s pretty bloody obvious from the pictureless LCD screen!

Frustratingly there is no way of reassigning functions to the several buttons inside the camera body so, for example, even if you don’t intend to use the Auto AE button, you can’t make it something more useful. You can, however, assign three touch-screen buttons to functions you require but these are (like the Canon HF-G30) access to menu options rather than on/off switches as might be preferred.

For example, assigning Peaking to a button simply brings up the Peaking menu through which you can then further select on/off, rather than simply being able to make the button an on/off toggle for that function. This is an issue because when filming live action events, faster access to the basic function can often be essential, leaving the configuration of that function (what colour you want the peaking, how sensitive it is) to a menu-driven, set-once-and-forget feature.

As is traditional for consumer-oriented camcorders, the CX900 offers a range of stylised “looks” which you can record your film in, though this is permanent once recorded and therefore we suggest should be avoided – much better to add colouration effects afterwards when editing since at least then you can try various styles and take them off if you don’t like them or change your mind!

We’re not sure if we like the CX900 or not. It’s very expensive, quite bulky, has poor stabilisation (unless you’re willing to trade this off with degraded image quality), no physical assignable buttons and no XLR audio inputs. Sony’s awkward hot shoe does it no favours either and the unattached lens cap is a nuisance as well. It also lacks niceties like a timelapse function.

On the plus side it’s got lots of physical controls – lens ring, exposure dial, exposure buttons, ND filter – and can shoot at 50 Mbps for great image quality. Low light performance is on a par with the state of the art but only a little better once you add gain. The trouble is that that’s where the plus points end. The negatives are quite a few in number and whilst the operation of the unit is quite flexible, we’re insufficiently enamoured to want to rush out and buy one.

When all’s said and done, despite the Sony’s cleaner gain we prefer Canon’s HF-G30 (despite its own shortcomings) or the XA20 version if you can stretch to it for the added bonus of XLR inputs.

Which one would you buy? Do so through our Amazon UK link and we get a small commission for which we’re pathetically grateful.

Here’s the CX900: (with the AX100 4K version at

Canon’s XA20:

And Canon’s HF-G30:

Here’s our all-in-one video review:

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