Sony RX100 Video

Sony RX100 Video Recording

High-definition video capture is now a must-have feature in large-sensor cameras, and essentially all the major manufacturers now provide some form of video capture in their interchangeable-lens cameras, as do the few making large-sensor fixed lens models. Sony's RX100 falls into the latter camp, and its feature set is pretty comprehensive. Capture is possible at up to Full HD resolution at a rate of 60 frames per second, with both optical zoom and autofocus available during capture. Exposure can be adjusted automatically or manually, both before and during capture. A control ring around the lens barrel allows adjustments with relatively little handling noise and jostling during capture, which is rather a bonus--many cameras that allow exposure adjustment during capture require use of physical controls that cause noticeable clicks and bumps. Audio comes courtesy of a stereo microphone on the top deck, and a wind noise filter is available. Unusually, you can capture high-res stills during video capture, without any interruption to the video itself. There are also some fun creative options such as Picture Effects and a background defocus tool which let you tweak the look of videos in-camera.

While it lacks a 720p capture mode, as well as the external microphone connectivity, manual audio levels control, and fine-grained frame rate control that professionals and more experienced enthusiasts will crave, the Sony RX100's video functionality is uncommonly comprehensive for a fixed-lens camera, and will doubtless satisfy most users.

Sony RX100 Basic Video Specs

• 1080p / 1080i (1,920 x 1,080) high definition video at 59.94p (progressive-scan) frames/second, or 59.94i (interlaced) fields / second (50p/i for European versions)
• 28 Mbps recording at 59.94p / 50p, choice of 24Mbps or 17 Mbps for 59.94i / 50i video modes
• HDV 1080i (1,440 x 1,080 rectangular pixels), 29.97 fps, 12 Mbps, HD recording (25 fps in European versions)
• VGA (640 x 480), 29.97 fps, 3Mbps standard-definition recording (25 fps in European versions)
• 1,920 x 1,080 video uses AVCHD compression (MPEG-4 AVC / H.264 w/ Dolby Digital audio) in a .MTS container; lower resolutions are MPEG-4 with AAC-LC audio in .MP4 container
• Maximum clip length is approximately 29 minutes; MPEG-4 video also stops after 2GB, but AVCHD spans new files every 2GB
• Full-time contrast-detect autofocus with tracking during video capture; manual focus also available
• Face detection available so long as digital zoom isn't in use
• Automatic, priority, or manual exposure modes
• Lens zoom, focus, shutter, aperture, ISO, and exposure compensation are all adjustable before or during video capture
• Both zoom and focus are relatively quiet, inducing only a fairly unobtrusive whirring sound
• Digital zoom is available, and cannot be disabled, although there is a brief pause between optical and digital zoom
• Control ring makes adjusting one exposure variable quiet and relatively shake-free
• Maximum sensitivity limited to ISO 3,200 equivalent for video capture
• SteadyShot image stabilization available, operates in Active mode for video capture, with greater corrective ability
• Exposure mode, white balance, creative style, some picture effects, metering mode, DRO, and image stabilization can be set before movie capture begins
• Stereo audio recording via built-in microphones on top deck
• Audio recording can be disabled altogether, and wind cut filter is available
• Still images can be captured without interrupting movie recording, except if using 60/50p modes; aspect matches that of movie, for maximum 17 megapixel resolution
• Smile shutter is available during movie recording, can be used to trigger still capture automatically
  
  

Sony RX100 Video: Image Size, Frame Rate, and Encoding

The Sony RX100 records at three different video resolutions, and can record high-definition movies in either AVCHD or MPEG-4 formats. Stereo audio is recorded during movie capture, encoded as Dolby Digital (AC-3) for AVCHD and AAC-LC for MPEG-4. No spec is provided for the sampling rate of the audio tracks, though video players report 16-bit, 48 kHz at 256 kbps for AVCHD and 16-bit, 48 kHz at 128 kbps for MPEG-4.

The table below shows the specs for various video recording options.

As noted above, the Sony RX100 offers two video recording formats, either the HD-only AVCHD format or the less space-efficient but more computer-friendly MPEG-4. The MPEG-4 file format is a bit less efficient in its use of memory card space for a given image quality level, but is more widely supported, and seems to be a bit easier for older computers to read. AVCHD is the best choice if your primary output is going to be directly to a HD television, but MPEG-4 probably a better choice for your computer, particularly if it's more than a couple of years old.

In AVCHD mode, the pixel resolution is 1,920 x 1,080, with a choice of either progressive-scan or interlaced capture. The highest 28Mbps bitrate is not surprisingly in the 60 frames-per-second progressive scan mode, and here you have no choice of lower bitrate. For interlaced video, though, you have two choices of bit rate; either 24 Mbps, or 17Mbps. The Full HD 60p 'PS' mode is beautiful--very smooth, with no interlacing and very few compression artifacts, but it does result in very large file sizes. (Our standard dog / frisbee shot came in at 3.6 megabytes / second.)

MPEG-4 mode offers a choice of two resolutions both recorded at 30 frames/second (progressive), with data rates and compression ratios as detailed in the table above. Note that the 1,440 x 1,080 pixel mode has rectangular pixels, meaning that it plays back with a standard 16:9 aspect ratio, but with reduced resolution on the horizontal axis. This less-common format hails from HDV camcorders. The MP4 mode offers very good rendering of subtle detail.

Unusually, the RX100 forgoes a 1,280 x 720 pixel mode altogether, and doesn't offer a choice of frame rate (beyond that dictated by your choice of NTSC or PAL versions, anyway) at any resolution.

Sony recommends use of a Memory Stick PRO-HG Duo, PRO Duo Mark 2 or Micro Mark 2 card, or SD / SDHC / SDXC / MicroSD / MicroSDHC Class 4 rated memory cards for movie recording, to ensure that card write speed isn't a limiting factor in clip length. (Slower cards will likely still work to some degree, but with a reduction in clip length, especially in AVCHD mode at the highest bit rates; many competitors actually recommend a minimum of Class 6 SD cards.)

Here are some examples of video shot with our sample of the Sony RX100:

Sony RX100 Video-Mode Focusing

Autofocusing is traditionally something of a bugbear for large-sensor cameras. Very few indeed can offer phase-detect autofocus during video capture, and with most interchangeable lenses having been designed with still imaging in mind, they typically bring drawbacks such as excessive AF drive noise when used for video capture.

With a fixed lens that was designed specifically for the camera, the Sony RX100 has less issues than most. It's still a contrast-detect system, and so there's some slight but noticeable hunting around the point of focus, as you'd expect. Its AF algorithm can also be a little slow to decide your subject's distance has changed enough to warrant a change of focus distance. That's likely better than the alternative of a hyperactive AF system that departs from your subject at the slightest provocation, though. Once an AF change is needed, the RX100 does so reasonably smoothly and quickly, and with little to no focus noise noticeable in your video clip.

It's worth noting that the RX100 also implements both autofocus tracking, and face detection--and both are available for video capture. However, there's a slight proviso with the latter: face detection is no longer available as soon as you stray beyond the limit of the optical zoom, and into the camera's digital zoom. (And you can't disable digital zoom entirely for video capture, so it's quite easy to use it by mistake.) You also can't change the focus point size.

Of course, you can choose to focus manually, and if you do so then this function is assigned to the control ring that encircles the outside of the lens barrel. It's a nice control that's pretty easy to turn without objectionable noise, but the fly-by-wire design and very long throw for manual focus make it a little tricky not to jostle the camera unless you're only making a very minor focus adjustment.

Sony RX100 Video-Mode Zoom

As noted, the key area in which the RX100 differs from typical large-sensor cameras is its built-in optical zoom lens. The lens doesn't have a mechanical zoom control, but it offers two methods in which to control zoom electronically, both functional during video capture. You can either use the zoom rocker on the top deck, surrounding the shutter button, or you can configure the control ring to adjust zoom level. We found the control ring to be easier to use for small zoom adjustments, but the zoom rocker better if you wanted to make a larger adjustment without jostling the camera.

Either way, the optical zoom adjusts rather more slowly during video capture than it does for stills, which leads to smoother and less distracting zoom operations. Fortunately the zoom motor is pretty quiet (or perhaps electronically damped), as well, because optical zoom operation causes only a faint whirring to be recorded on the audio track of RX100 videos.

Sony RX100 Video Exposure Control

While the Sony RX100 lets you record movies directly from any of its still-image exposure modes, including aperture-priority, shutter-priority, and full manual exposure modes, the shutter speed, aperture, and ISO settings for video recording are always automatically controlled except when the Mode dial is in the Movie position, and autofocus is disabled.

In the dedicated Movie mode, it does provide direct control over the shutter speed, aperture, ISO, and exposure compensation settings for video recording, as appropriate to the current exposure mode. Perhaps even more unusually, it also provides these controls not only before capture starts, but actually during capture. It also previews the video aspect ratio in this mode, where in other modes there's no way to preview video framing until capture starts.

There are, of course, some provisos. The ISO sensitivity range is reduced to ISO 125 to 3,200 equivalents during video capture, and Auto ISO isn't available in Manual mode. The slowest available shutter speed is 1/4 second, and if a shutter speed below the video framerate is selected, this obviously has an effect on the perceived frame rate. (The actual video frame rate isn't reduced to match the shutter speed, however.) By using the control ring, handling noise when changing these exposure variables can be kept to a minimum, and the steps between exposure levels--while certainly still noticeable--are reasonably smooth as well, rather than the instantaneous changes found on some competing cameras.

The ability to quickly make adjustments to exposure settings without first having to stop video recording is pretty cool, and extremely rare for a fixed-lens camera.

White balance settings also carry over to video mode, as do the tone/color aspects of the camera's various scene modes.

Sony RX100 Movie-Mode Image Stabilization

The Sony RX100 includes the company's lens-based Optical SteadyShot image stabilization technology. Sony hasn't yet stated a claimed corrective range for the system in the RX100, but for video use the correction can be generous indeed--enough to correct for motion when walking, for example. That's because the system can operate in either Normal or Active modes, the latter being available only for movie use. The Active mode does, however, involve a greater focal length crop, resulting in 35mm-equivalent focal lengths ranging from 33 to 120mm, versus 29mm to 105mm for standard or unstabilized 16:9 video.

Since the RX100 uses sensor data to provide a live view feed on the LCD display or electronic viewfinder during video capture, the effect of stabilization can be monitored.

Sony RX100 Video: Audio recording

The Sony RX100 can record audio via an internal, stereo microphone, comprised of two separate microphones located on the top panel, adjacent to the popup flash and Power button. (Although we don't have an objective way to test this, the greater separation compared to that of the stereo mic designs in some competing models seems like it may provide better stereo effect.) As you'd expect in a camera aimed at keeping body size to a bare minimum, the RX100 doesn't provide for recording via external microphones, so if you want off-camera sound, you'll need to resort to a separate audio recorder, and switch audio tracks in post processing.

Sony's only published spec for the RX100's audio recording capability simply says Dolby Digital (AC-3) for AVCHD and AAC-LC for MPEG-4, so we don't officially know the sampling rate or number of bits of A/D resolution employed, although third-party MPEG players suggest a 16-bit, 48 KHz sample rate at either 256 kbps for AVCHD clips, or 128 kbps for MPEG-4 clips. Audio recorded with the camera's internal mic sounded very clear, but we do no tests to measure frequency response or sensitivity, so can't comment quantitatively.

We noticed only a fairly subtle hiss in audio tracks recorded with the in-camera mic, even in very quiet environments, where competing models sometimes introduce a significant level of hiss. The camera's auto-gain system also did a good job of adjusting sensitivity as sound levels got louder or softer, with no evident "breathing" in transitions from high to low sound levels. As noted above, the autofocus system on the RX100's lens was close to silent, and there was only a faint whirring when zooming the lens.

As with most of its competitors, the Sony RX100 doesn't have any provision for manual audio level control. While we don't think this will be an issue for most potential RX100 buyers, it's perhaps something of a shame given the exceptional level of control elsewhere. It is, however, possible to disable audio capture altogether, and there's also an optional Wind Cut filter function.

Sony RX100 Video: Creative Options

Several of the RX100's Picture Effect functions are applicable not only to still images, but also to movies. These include Toy Camera, Pop Color, Posterization, Retro Photo, Soft High-key, Partial Color, and High Contrast Monochrome. There is a proviso, however. When using a Picture Effect, the Dual Record function--we'll come to that in a moment--is not available. Picture Effects available for still image shooting only include Soft Focus, HDR Painting, Rich-tone Mono, Miniature, Watercolor, and Illustration; none of these can be used for movie shooting.

Additionally, the RX100's Background Defocus function, part of the Photo Creativity mode, can be used for video capture. Background Defocus can be adjusted both before and during recording. The other Photo Creativity tools--Brightness, Color, Vividness, and Picture Effect--apply only to still images, however.

Sony RX100 Video: Dual Record

The RX100 is extremely unusual in being able to capture high-resolution images during video capture, without interruption to its video feed--"Dual Record" in Sony parlance. These images can be captured at the camera's full sensor resolution, but with an aspect ratio crop identical to that used for video. That translates to a maximum resolution of 17 megapixels when shooting 16:9 video, or 13 megapixels when shooting VGA (4:3) video. You can also opt for a reduced resolution of 4.2 megapixels in 16:9 aspect, or 3.2 megapixels in 4:3 aspect.

If that's rare, another feature of the Dual Record function is downright unheard-of. (Or at least, we can't think of a camera which has offered it before.) The RX100's Smile Shutter function can continue to operate during movie recording, and will capture high-res still images whenever your subject smiles, without interruption to the video feed. Since it's based on face detection, which doesn't work when digital zoom is active, the Smile Shutter function will also stop working as soon as you've used the digital zoom. The Smile Shutter functionality for movies is available only while the video is currently being recorded, and with the camera in the dedicated movie mode. In other modes, and when movie capture isn't currently active, photos won't be captured.

Sony RX100 Movie Recording/Playback User Interface

The Sony RX100 makes movie recording very easy, as you can initiate it at any time, regardless of the mode-dial setting: Simply press the prominent Movie Record button with the red dot at its center at top right of the camera's rear panel, and the camera will start recording video. Of course, if you want to record with manual exposure control and a preview of your aspect ratio, as well as with some of the more advanced functionality such as Dual Record, you can jump to the dedicated Movie position. You get the best of both worlds--quick access while shooting stills, but total control when needed.

The RX100's dedicated Movie menu is short and sweet. A full list of options can be found below:

Sony RX100 Movie Menu:

Playback mode on the Sony RX100 is--as in other recent Sony interchangeable-lens cameras--decidedly odd. The reason is that the RX100's playback is an either/or (well, either/either/or) proposition, relative to stills and videos: If you've just shot a video and press the playback button, you'll see only movies that are stored on the card; not the still images. (And for that matter, only videos recorded with the same compression type you last used.) Likewise, if you've just shot a still image, you'll only see other stills when you hit the playback button.

To switch between the still, MP4, and AVCHD playback modes, you have several options -- either drop into thumbnail view and scroll over to the left, then press the four-way controller to get the Still / Movie Select screen, or visit the Playback menu and access Still / Movie Select there, or simply grab a throwaway exposure of the type you want to view. We actually found it much more convenient to hit the Movie Record button twice (to record a brief video clip) than to navigate through the playback menu to change the playback mode.

Sony introduced this playback mode in its NEX-series SLD cameras, where it caused us some consternation until we figured out what was going on. "Where'd all my movies/stills go?" RTM, as they say, but we can only imagine the dismay many users will experience (if only until they read the manual) when they think all their vacation photos disappeared after they'd finally shot a video. Since so few people actually do read manuals, we still suspect this is the source of a lot of service calls to Sony's support centers. Perhaps even more than ever for the RX100, because it doesn't come with a full manual, even as a PDF file, and the very abbreviated manual glosses over it very quickly indeed. (To get to the detailed, HTML manual, you have to open your web browser and visit the Sony Support website.)

Suffice to say, we're getting a bit tired of complaining about this design; it's unintuitive, awkward, and we find ourselves disliking it a little more with every generation of cameras that retains it. ;-)

We also still miss another playback option that's utterly commonplace on both digicams and SLDs from most manufacturers; namely the "trim" function. Whenever you record a short video clip, it's inevitable that you'll start earlier and keep recording longer than the action you're interested in. (If you don't do this, you're quite likely to miss action you're interested in.) While "padding" like this is important and necessary, we like to keep our videos concise by trimming away the extraneous material at the beginning or end of the clip after they're recorded. Many cameras support doing this in-camera these days, but the RX100 does not. You could certainly import the video clips to your computer and do the trimming there, but that's awfully cumbersome. Far easier to simply trim and toss away the unwanted footage on the camera.

Rolling Shutter Artifacts

Although rolling shutter is present in the Sony RX100's video, it's controlled pretty well. Not the best we've seen, by any means, but considerably better than most.

Essentially every video capable digital SLR/SLD currently on the market exhibits some level of motion-related distortion called rolling shutter artifacts. These are caused because the image data is captured and then read off the chip sequentially by rows, rather than each frame's data being captured all at once. In the case of the Sony RX100, this means that image data for the last row of a given frame is captured and read out anywhere from 1/30th to 1/60th second after the data for the top row was captured. The effect on moving objects is like that of a focal plane shutter in an SLR, but more pronounced, because the video frame is read out much more slowly than the slit of a focal plane shutter moves across the sensor.

For a camera that scans video frames vertically (as all do that we're aware of), rolling shutter artifacts will be most noticeable for subjects that are moving rapidly side to side, or when the camera itself is being panned horizontally. Verticals in the scene will appear tilted to the right or left, depending on the direction of camera motion. As an example, consider the case of a camera being panned from left to right, with a flagpole or other vertical object in the middle of the scene when recording for a particular frame begins: If the top of the object was centered horizontally when the first line of the video frame is acquired, by the time the last line of the frame has been captured, the bottom of the object will have shifted to somewhere left of center: As a result, the vertical object would appear to be leaning to the right.

Computer Requirements for Viewing HD Video

A typical computer these days has little trouble dealing with still images, but high-definition video can be another matter. Depending on the file format involved, it can take a pretty beefy computer to handle HD-resolution video playback without stuttering or dropping frames. The Sony RX100 supports both AVCHD and MPEG-4 recording formats, but the choice is dictated for you by resolution. The AVCHD format used at the highest resolution is slightly more space-efficient on the memory card, and displays well on HD television sets, but is one of the more compute-intensive formats, and its 1,920 x 1,080 (1080p) resolution with 60 frames per second capture rate means there's a lot of data to deal with. The net result is that you'll want a recent, powerful computer to play full-res, 60p high-def video files from the RX100 on your computer. For lower resolution MPEG-4 video, the requirements will be somewhat more modest. You can, of course, view your movies on an HDTV via the HDMI output.