Sony NEX-F3 Video Recording

High-definition video capture has become a must-have feature in this year's interchangeable-lens cameras, and essentially all the major manufacturers now provide some form of video capture in their compact system cameras. Although positioned as an affordable, consumer camera, the Sony NEX-F3 includes some more advanced features including full manual exposure control and external microphone support, along with consumer-friendly options such as full-time autofocus, and a wind noise filter. Although it does lack audio levels control, standard microphone connectivity, and the fine-grained control over framerates that are sometimes found on competing models, these features would likely be overkill for its target market.

As a consumer system camera, the Sony NEX-F3 provides a useful feature set that offers amateur and even some prosumer videographers plenty of room to grow and experiment with new techniques.

Sony NEX-F3 Basic Video Specs

• 1080i / 1080p (1,920 x 1,080) high definition video at 59.94i (interlaced) fields / second or 23.976p (progressive-scan) frames/second (50i / 25p for European versions); choice of 24Mbps or 17 Mbps bitrate
• 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 and recognition available so long as digital zoom isn't in use
• Automatic, priority, or manual exposure modes
• Autofocus, AF tracking, shutter, aperture, ISO, exposure compensation, and digital zoom are all adjustable before or during video capture
• Autofocus and aperture adjustment are essentially silent
• Manual optical zoom available if supported by lens; Digital zoom is available in 0.1x steps to 4x max.
• Maximum sensitivity limited to ISO 3,200 equivalent for video capture
• SteadyShot image stabilization available if supported by lens
• 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; proprietary external microphone available, mounts on top deck accessory terminal
• Audio recording can be disabled altogether, and wind cut filter is available
  
  

Sony NEX-F3 Video: Image Size, Frame Rate, and Encoding

The Sony NEX-F3 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 48 kHz at 128 kbps for MPEG-4.

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

Sony NEX-F3 Video Options
AVCHD Format (.MTS files)
Menu Designation	Resolution	Frame Rate	Approx. Bitrate
60i / 50i 24M (FX)	1,920 x 1,080 (16:9 aspect ratio)	59.94i / 50i	24 Mbps
60i / 50i 17M (FH)		59.94i / 50i	17 Mbps
24p / 25p 24M (FX)		23.976p / 25p	24 Mbps
24p / 25p 24M (FH)		23.976p / 25p	17 Mbps
MPEG-4 Format (.MP4 files)
Menu Designation	Resolution	Frame Rate	Approx. Bitrate
1440x1080 12M	1,440 x 1,080 (16:9 aspect ratio, 1.33:1 aspect rectangular pixels)	29.97p	12 Mbps
VGA 3M	640 x 480 (4:3 aspect ratio)	29.97p	3 Mbps

As noted above, the Sony NEX-F3 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 60 / 50 fields per second interlaced, or 24 / 25 frames per second progressive-scan capture, depending upon whether you have an NTSC or PAL camera. You have two choices of bit rate; either 24 Mbps, or 17Mbps.

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.

Unusually, the NEX-F3 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 or PRO Duo Mark 2 card, or SD / SDHC / SDXC 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.)

Daytime video from the NEX-F3 doesn't strike us as being quite as clean as that from the NEX-F3 or some other compact system cameras, but this is a relatively minor gripe. Here are some examples of video shot with our sample of the Sony NEX-F3:

Sony NEX-F3: Video Samples
1,920 x 1,080 'FX' Interlaced, 60 fields per second Download Original
1,920 x 1,080 'FH' Interlaced, 60 fields per second Download Original
1,920 x 1,080 'FH' Progressive, 24 fields per second Download Original
1,440 x 1,080 Progressive, 30 frames per second Download Original
640 x 480 Progressive, 30 frames per second Download Original
1,920 x 1,080 'FX' Interlaced, 60 fields per second Download Original
1,920 x 1,080 'FX' Progressive, 24 fields per second Download Original
1,440 x 1,080 Progressive, 30 frames per second Download Original
640 x 480 Progressive, 30 frames per second Download Original

Sony NEX-F3 Video-Mode Focusing

As with previous NEX-series cameras, consumer videographers will appreciate the Sony NEX-F3's live autofocus during recording. Although pros and many advanced amateurs can "pull focus" (adjust the focus manually) while filming video--and indeed may well prefer to do so, considering focus to be another means of expressing their artistic vision--it's very much a learned skill, and something few people ever manage to do really well. Without live AF, consumers for the most part are reduced to only shooting subjects at a constant distance from the camera, or to having to settle for a lot of poorly-focused video. A lot of video-capable interchangeable-lens cameras are sold to consumers these days, and while having some video capability is certainly better than none, for most consumers to make full use of a video-capable camera it really needs to be able to focus on the fly.

With the NEX series, Sony's engineers had video recording in mind from the earliest stages of development. E-mount lenses use low-mass focusing elements and high-speed stepper motors to give the rapid response required for live contrast-detect focusing during video recording. (They also employ a continuously-variable aperture mechanism, to provide stepless exposure control, another key issue for video recording.)The result is a fairly competent autofocus system that should meet the demands of most consumers, especially considering the NEX-F3's affordable pricing.

The Sony NEX-F3 allows either full-time autofocus, or manual focus. Although you can prompt an immediate autofocus operation in full-time AF mode by half-pressing the shutter button, you can't opt to focus manually but with single AF operations as needed. You can, however, adjust the autofocus area (multi, center, or flexible spot), and use autofocus tracking (unless in flexible spot mode). Interestingly, you can start and stop tracking AF during capture, although your subject must start from the center of the frame. You can also adjust the flexible spot location during capture. Additionally, the NEX-F3 provides face detection autofocus with the ability to recognize specific individuals that you've programmed into the camera, and all this functionality is available for video capture as well.

We found that the NEX-F3's tracking function worked quite well, at least in daylight shooting. The continuous AF did hunt a fair bit when shooting our standard street scene at night, though. That's perhaps because we pan the camera; it settled down pretty well once motion stopped.

Sony NEX-F3 Video Exposure Control

Sony NEX-F3: Aperture Control / Depth-of-Field
1,440 x 1,080 Progressive, 30 frames per second, f/3.5 Download Original
1,440 x 1,080 Progressive, 30 frames per second, f/22 Download Original

 

The Sony NEX-F3 lets you record movies directly from any of its still-image exposure modes, including aperture-priority, shutter-priority, and full manual exposure modes, and unlike many competitors, it does actually 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. This is really cool, letting you unleash your creative side!

There are, of course, some provisos. The ISO sensitivity range is reduced to ISO 200 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.) It's also worth noting that while Program Shift is available for still imaging, it isn't applicable to video capture. Also, with the built-in microphone, handling noise is clearly audible when changing any of these exposure variables, and they do cause clear shifts in image brightness if adjusted during capture. Still, the ability to quickly make adjustments to exposure settings without first having to stop video recording is pretty cool, and any unwanted portions can always be edited out of the video in post-processing, should handling noise or exposure level changes prove too objectionable. We found that the NEX-F3 did a better job of exposing our night sample videos than do a lot of competing compact system cameras.

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

Sony NEX-F3 Video-Mode Zoom

Of course, the Sony NEX-F3 lets you use optical zoom if an appropriate lens is mounted, but since it has yet to offer a power zoom lens for E-mount, there's usually some degree of jostling involved. (The degree will depend on the lens in use, and your skill at steadying the camera with one hand will turning the zoom ring with your other hand.) On the plus side, with a solely manual, mechanical zoom operation, you have full control over zoom speed, and the degree of operation noise is minimal indeed.

The NEX-F3 also allows use of its 4x digital zoom during capture, although as with exposure control, the lack of a rocker control means that there's some handling noise involved. The digital zoom isn't completely stepless, but operates in reasonably fine-grained 0.1x steps.

 

Sony NEX-F3 Movie-Mode Image Stabilization

Sony's unique among camera manufacturers, in having both body-based and lens-based image stabilization technology in their product lines. In the case of the NEX-F3, image stabilization happens in the lens, so its availability will be a function of the particular lens used. Among the company's E-mount lens lineup, all of the zoom lenses offer nearly silent lens-based IS. Among the primes, only the 50mm lens offers stabilization. Using the 18-55mm kit lens, even in extremely quiet scenes, we were unable to hear any trace of the IS system in the NEX-F3's captured sound track.

Sony NEX-F3 Video: Audio recording

The Sony NEX-F3 can record audio via an internal, stereo microphone, comprised of two separate microphones located on the front panel, above the lens mount. (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.) The NEX-F3 also provides for recording via an external stereo microphone, attached via the Smart Accessory Terminal 2.0 socket on the camera's top deck. Currently, only a proprietary Sony external mic (shown above right on the earlier NEX-5 camera body) can be connected to this jack. We still hold out hope that Sony will eventually offer an adapter for the common 3.5mm stereo phone plug standard, although they've yet to do so.

Sony's only published spec for the NEX-F3'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 NEX-F3'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 NEX-F3 doesn't have any provision for manual audio level control. While we don't think this will be an issue for most potential NEX-F3 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 NEX-F3 Video: Creative Options

Several of the NEX-F3'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. Picture Effects available for still image shooting only include Soft Focus, HDR Painting, Rich-tone Mono, and Miniature; none of these can be used for movie shooting.

Additionally, the NEX-F3'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 NEX-F3 Movie Recording/Playback User Interface

The Sony NEX-F3 makes movie recording very easy, as you can initiate it at any time, regardless of the exposure mode setting: simply press the prominent Movie Record button with the red dot at its center at rear right of the camera's top panel, and the camera will start recording video.

Normally, this is where we'd list the Movie-mode menu items, but the NEX-F3 has no separate movie menu. In fact, the only menu items exclusively related to video recording are the choice of file format (AVCHD or MP4), image size (1,920 x 1,080, 1,440 x 1,080, or 640 x 480 pixels), and frame rate / compression level (if recording at the higher resolution), as well as options to disable audio recording, and to enable the wind cut filter. (And somewhat confusingly, the latter two options are hidden in the Setup menu.)

Playback mode on the Sony NEX-F3 is--as in other recent Sony NEX-series cameras--decidedly odd. The reason is that the NEX-F3'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 NEX-F3, 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 NEX-F3 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

Sony NEX-F3: Video Samples
1,920 x 1,080 'FH' Interlaced, 60 fields per second Download Original
1,920 x 1,080 'FH' Progressive, 24 fields per second Download Original
1,440 x 1,080 Progressive, 30 frames per second Download Original
640 x 480 Progressive, 30 frames per second Download Original

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 NEX-F3, 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. While rolling shutter is present in NEX-F3 video, it's controlled pretty well. Not the best we've seen, by any means, but considerably better than most.

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 NEX-F3 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 fields 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, 60i high-def video files from the NEX-F3 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.