Panasonic G2 Video Recording

Panasonic pioneered advanced video capability in compact SLD (Single Lens Direct-view) cameras, in that their DMC-GH1 was and still is (as of this writing in late April, 2010) the only interchangeable-lens camera with truly effective "live" autofocus during video recording. That capability has been shared by subsequent Panasonic models, but full capability still does depend on the exceptional AF speed of the special "video-capable" Lumix 14-140mm zoom lens that shipped with the GH1. With slower-focusing lenses, the new Panasonic DMC-G2 may not be able to track motion as well, and the motors in some lenses may be audible in the sound track, but the Panasonic G2 generally does a better job of focus tracking during video than most of its competitors. (And of course, you're always free to focus manually, if you'd like to guide the viewer's attention more directly.)

While it doesn't provide the full PASM exposure control of the earlier GH1, it does offer at least some control over both aperture and shutter speed. Unlike some of its competition, the Panasonic G2 also provide a stereo microphone jack for connecting to an external microphone; either Panasonic's own DMW-MS1 model or a third-party unit with compatible signal levels. For video enthusiasts, the most significant limitation is that its maximum video resolution is 720p (1,280 x 720 pixels, progressively scanned), vs the "Full HD" spec of 1080i (1,920 x 1,080 pixels, interlaced).

While it may not provide the level of exposure control demanded by pros and high-end video enthusiasts, we believe the Panasonic G2 offers a really compelling package of video features for the average consumer. Its smooth focus tracking ability in particular will make it more appealing to the average user than most of its competitors.

Panasonic G2 Basic Video Specs

• 720p (1,280 x 720), 60 fps HD recording, but derived from 30 fps sensor output (50 fps in Europe, derived from 25 fps sensor output)
• 848 x 480, 640 x 480, 320 x 240 at 30 fps SD recording
• Option of either AVCHD or Motion JPEG recording formats
• Autofocus is possible during recording, with variable results depending on the lens used (live AF tracking is much better than most competitors, though, even with the kit lens)
• Programmed-only exposure (that is, no true aperture-priority or shutter-priority)
• "Peripheral Defocus" adjustment (in Movie P mode only) does let you bias the exposure system toward larger or smaller apertures, achieving much the same effect as aperture-priority exposure mode on other cameras
• Flicker Reduction (also in Movie P mode only) does let you choose shutter speeds of 1/50, 1/60, 1/100, 1/120 second, providing limited shutter-priority mode. (As the name suggests, this is intended primarily for avoiding video flicker from fluorescent lights.)
• EV adjustment is available in all movie recording modes, and can be adjusted during recording.
• Monaural audio recording via built-in microphone, plus external stereo input via 2.5mm phone jack.
• Up to 20 two-megapixel resolution still images can be captured during each video recording session (when recording is started from a still-image capture mode).
  
  

Panasonic G2 Video: Image Size, Frame Rate, and Encoding

Panasonic G2 Video Resolutions & Recording Formats

The Panasonic G2 records a variety of resolutions and frame rates, using either the more space-efficient AVCHD Lite or the more broadly compatible Motion JPEG file formats. The frame rate is always 60 fps in the US and 50 fps in Europe, but note that, while the frame rate for AVCHD is 60 or 50 fps in the files, the sensor is capturing at 30 or 25 fps respectively, and the additional frames are created by doubling the frames coming from the sensor. No spec is provided for the sampling rate of the audio track during movie recording, though video players report 16-bit PCM audio at 16 kHz for Motion JPEG, and 48 kHz Dolby Digital at 192 kbps for AVCHD Lite.

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

Panasonic Lumix DMC-G2 Video Options
AVCHD Lite Format (.MTS files)
Menu Designation	Resolution	Frame Rate	Card Capacity
SH	720p 1,280 x 720	60 fps (sensor output is 30 fps) 17 Mbps	2.1 MB/second (15.5 minutes on 2GB card)
H	720p 1,280 x 720	60 fps (sensor output is 30 fps) 13 Mbps	1.6 MB/second (20.5 minutes on 2GB card)
L	720p 1,280 x 720	60 fps (sensor output is 30 fps) 9 Mbps	1.1 MB/second (29 minutes on 2GB card)
Motion JPEG Format (.MOV files)
Menu Designation	Resolution	Frame Rate	Card Capacity (very approximate)
HD	1,280 x 720 (16:9 aspect ratio)	30 fps	~~3-4 MB/second (~9 minutes on 2GB card)
WVGA	848 x 480 (16:9 aspect ratio)	30 fps	~~1-2 MB/second (~25 minutes on 2GB card)
VGA	640 x 480 (4:3 aspect ratio)	30 fps	~~0.8-1.2 MB/second (~35 minutes on 2GB card)
QVGA	320 x 240 (4:3 aspect ratio)	30 fps	~~0.5 MB/second (~65 minutes on 2GB card)

As noted above, the Panasonic G2 offers two video recording formats, either the HD-only AVCHD Lite format or the less space-efficient but more computer-friendly Motion JPEG. The Motion JPEG file format is much less efficient in its use of memory card space, but is more easily read by older computers. AVCHD Lite is the best choice if your primary output is going to be directly to a HD television, but Motion JPEG will be easier for your computer to read, particularly if it's more than a year or two old. (As you can see from the table above, though, Motion JPEG files take up quite a bit more space for a given pixel resolution.)

In AVCHD Lite mode, the pixel resolution is always 1,280 x 720, but the compression varies depending on the quality level selected. The three quality levels (SH, H, L) correspond to the three standard bit rates called out in the AVCHD Lite spec, namely 17, 13, or 9 Mbps (megabits/second). In our experience with cameras recording in the AVCHD Lite format, we've generally found that the video artifacts associated with quality settings below 17 Mbps generally weren't worth the savings in file size: Unless you're cramped for memory card space, we really recommend using the Panasonic G2 at its highest AVCHD quality setting. As noted above, AVCHD Lite files in the G2 are always recorded at a 60 fps frame rate for NTSC and a 50 fps frame rate when the camera is set to European PAL timing, although the sensor itself only outputs data at 30 or 25 fps respectively. Note that Panasonic doesn't include a switchable video output mode in North American cameras, but those intended for sale in other markets may allow a choice of either NTSC or PAL video encoding.

Motion JPEG offers a choice of four file sizes, as detailed in the table above, all recorded at 30 frames/second, with the sensor capturing data at that same rate. Due to its higher data rates, Panasonic cautions in the manual that Motion JPEG recording requires at least a Class 6 SD memory card, while AVCHD Lite needs a speed rating of only Class 4.

While the Panasonic G2's HD mode doesn't offer the higher-resolution 1080i HD option, that may not be much of a sacrifice: We've found that 1080i recording in digicams and SLRs often brings with it either unacceptable levels of compression artifacts in the face of even modest amounts of movement in the frame, reduced frame rates, or both. The Panasonic G2's 30 fps sensor output is faster than some cameras that are limited to the 24 frames/second "cinema" standard, but it doesn't match the level of smoothness and motion-capture ability offered by models sporting 60 frames/second sensor output. In both frame rate and resolution, it ranks roughly in the middle of the pack of current interchangeable-lens video-capable cameras. (Although some people prefer or need the 24 fps standard, either for its more "film-like" look, or because they're pros who need to mix their videos in with other clips shot on film.)

Here are some examples of video shot with our sample of the Panasonic DMC-G2:

Panasonic G2 Video Samples
AVCHD SH quality (1,280 x 720) (16.4 MB)	Motion JPEG HD resolution (1,280 x 720) (40.3 MB)
AVCHD H quality (1,280 x 720) (14.3 MB)	Motion JPEG WVGA resolution (848 x 480) (12.6 MB)
AVCHD L quality (1,280 x 720) (9.6 MB)	Motion JPEG VGA resolution (640 x 480) (13 MB)
	Motion JPEG QVGA resolution (320 x 240) (5.6 MB)
Peripheral Defocus - Soft Motion JPEG, HD quality (17.6 MB)	Peripheral Defocus - Sharp Motion JPEG, HD quality (26.2 MB)
Focus Tracking Example Motion JPEG, HD quality (27.8 MB)	Rolling Shutter Artifact Example AVCHD, SH quality (8.4 MB)
Night Video, AVCHD AVCHD SH quality (9.0 MB)	Night Video, Motion JPEG Motion JPEG HD quality (22.2 MB)
This is a pretty dark shot, captured under slightly dimmer than average city street lighting. Some cameras can manage it, albeit with a fair bit of noise; some can handle it cleanly. The Panasonic G2 recorded a clean-looking movie, but the scene was really below what the camera could handle in video. (Note, though, that the interior recorded pretty well, so the G2 should work fine in well-lit interiors at night.)

Panasonic G2 Video-Mode Focusing

As with the GH1 and GF1 before it, consumers will doubtless find the Panasonic G2's live autofocus during recording an important feature. Pros and 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. Doing it well is very much a learned skill, though, and something few people ever learn 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 SLRs are certainly being sold to consumers these days, and having some video capability is certainly better than none, but for most consumers to make full use of a video camera, it really needs to be able to focus on the fly.

As I noted in our review of the Panasonic GH1, the Panasonic engineers really had video recording in mind from the very beginning of Micro Four Thirds development. As a result, Panasonic SLD cameras have to date had an edge in video-mode focusing, and the G2 is no exception. For the most responsive video focus-tracking, you'll need a special video-specific lens, such as the 14-140mm model that's sold as part of the kit with the GH1: The lens has to have a very responsive AF motor to be able to complete an AF cycle within the 1/30 second readout cycle of the G2's sensor. That said, though, we found that even the 14-42mm kit lens did a surprisingly good job tracking moving subjects. The crops below show how well the Panasonic G2 did tracking the official IR mascot Charlotte, as she retrieved a frisbee. It wasn't perfect (and the crops below of individual frames are the video equivalent of pixel-peeping), but on the whole it did pretty well.

Panasonic G2 Video: Tracking Autofocus (NOTE: Shot with 14-42mm kit lens, not video-specific 14-140mm)
I didn't start the camera rolling until Charlotte had rounded the corner, figuring to give it a solid starting point. As it turned out, though, I'd had it in continuous AF mode and had it aimed elsewhere prior to the start of the clip, so the beginning of the clip is a bit out of focus, while the camera was slewing focus to the correct setting.	A little bit into the clip, the camera has found the right focal point, and is tracking reasonably well.
Like any contrast-detect AF system, though, the G2's will "hunt" while recording, as it tries to find the best point of focus. In this frame, it was actually front-focused by quite a bit.	A few frames later, the G2 found Charlotte again, and tracked her fairly well until she was a good bit closer to the camera. While the frame on the left was fairly out of focus, it's not all that obvious in the live video, with all the motion going on.
The G2 stayed pretty well focused on Charlotte as she got closer...	This might be a slight back-focus (some of the fur on her body looked a bit sharper), but it might also be motion blur, as the camera was panning fairly rapidly here, and Charlotte herself was moving pretty rapidly.
This is probably my fault more than the camera's: I had the center AF point selected, and in this part of the clip, the grass in the background was more in the center of the frame than was Charlotte.	Once Charlotte was back in the center of the frame, it took perhaps a second or so for the G2 to refocus properly. This is a frame showing about the worst-case misfocus during that time.
Here's the camera properly focused again; a crop from a frame about 3/4 second from the end of the clip.	Like all contrast-detect AF systems, the G2's has to "hunt" a little to make sure it has the best focus. This crop is from a frame about a quarter-second later than the previous one, showing Charlotte slightly back-focused. The G2's hunting was pretty subtle (even with the non-video-specific kit lens), and not very visible when viewing the live video.

The above shots were all cropped from Motion JPEG frames captured at HD resolution (1,280 x 720 pixels) and are shown 1:1 on-screen. As you can see, while the camera didn't do a 100% perfect job of tracking the action, it stayed pretty darn close most of the time: Certainly similar to what we'd typically expect from a consumer camcorder, and well within the limits of what we'd find acceptable for casual video snapshots and family memory-recording. The camera obviously lagged the action slightly at the end of the clip, and was thrown off by seeing the background grass under its active AF point as Charlotte made the handoff to Marti, but it wasn't too far out at that point, and caught up within just a second or so. As shown in the last couple of crops above, you can see the focus system hunting a bit here and there, but it's not nearly as pronounced as we've seen in some competing models, and for the most part wasn't very noticeable when the movie was playing. (As noted above, grabbing individual frames from the middle of a video stream is the video equivalent of pixel-peeping 1:1 crops from multi-megapixel still frames.) Overall, it's a very practical video AF system for consumer movie recording.

We also found that we appreciated the Panasonic G2's touch-select movable focus point as much or more for video recording as we did when shooting still images: We've honestly never been particularly big fans of touch-screen interfaces on cameras, but the way Panasonic implemented theirs on the is very fluid and natural, and really makes a lot of sense. We especially liked that we could use the touch-select focus to change the point of focus in the frame while video recording was in progress, at least with the AF knob set to the 23-point option: We could start with the camera focused on a foreground object on one side of the frame, and then have it transition smoothly to focusing on a background object on the other side of the frame, simply by touching the other side of the LCD screen. The advantage of this is that our finger caused no noise on the audio track, other than the operation of the focus motor itself. This is a nice contrast to systems where shifting the focus would require either manual manipulation of the lens or pressing buttons on the camera's user interface, either of which would produce clearly audible noise on the audio track.

Bottom line, the Panasonic G2 is a great "hybrid" video/still camera. Usable autofocus tracking during video recording is a big deal for consumers. Video-capable SLRs and SLDs with non-tracking AF are certainly a long ways ahead of non video-capable models when it comes to recording family memories and other amateur video, but workable tracking AF will result in less frustration and more recorded memories for mass-market users.

Panasonic G2 Video Exposure Control

While the Panasonic G2 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. Thus, while the controls might suggest full PASM (programmed, aperture-priority, shutter-priority, and full manual exposure) exposure control for videos, the only mode that gives you some control over depth of field is "Motion Picture P" mode, indicated by the movie-camera icon with the letter 'P' following it on the mode dial.

In Motion Picture P mode, you can access the Peripheral Defocus control via the rear-panel control dial. Normally, pressing this dial activates the exposure compensation adjustment, or toggles between aperture and shutter speed in Manual exposure mode for still images. Once you've selected the parameter you want, rotating the wheel makes the setting. In Motion Picture P mode, pressing the dial a second time brings up a display for setting Peripheral Defocus. Here, "Peripheral Defocus" really just means the camera shifts its exposure curve to one emphasizing larger apertures: As far as we can tell, the G2 doesn't apply to videos the sort of in-camera processing used in its still-image Peripheral Defocus still-capture scene mode to programmatically blur background objects.

Panasonic G2 Video: "Peripheral Defocus" (Depth of Field Control)
Available only in Motion Picture P mode, the Peripheral Defocus setting lets you bias the G2's video exposure curve towards larger or smaller apertures. Here we've set it for maximum blurring (large aperture). The kit lens doesn't have a very large maximum aperture, but it does provide some DOF control.	Here's a shot from the same position, with Peripheral Defocus set all the way to the "sharp" end of the scale. You can see that the depth of field is greatly increased, albeit at the cost of a little sharpness overall. (We're pretty sure the camera's focus was centered on Charlotte's face here, vs focused more towards the background.) The slight softening overall is likely due to diffraction limiting in the lens from the small aperture.

While it's a bit buried in the user interface, and a little obscured (in our view) by calling it Peripheral Defocus, the ability to control depth of field during movie recording is a great feature, and one that's lacking in many competing camera models. A shallow depth of field helps you control where your viewers' attention is drawn within the frame, and the tiny sensor chips on most camcorders make this almost impossible to achieve.

On the shutter-speed side, another feature in Motion Picture P mode gives you at least a little control over shutter speeds. Pressing the aperture/trash can icon button in the lower right corner of the rear panel enables or disables Flicker Control, which lets you choose shutter speeds of 1/50, 1/60, 1/100, and 1/120 second for movie recording. These are intended to help in controlling video flicker caused by fluorescent lighting, but can also be used to gain at least a measure of direct control over shutter speed.

In addition to the conventional exposure modes, the Panasonic G2 offers many of its still-image scene modes for video recording as well. Available options include SCN mode (with its sub-options of Party, Baby 1 & Baby 2, Pet and Peripheral Defocus), Portrait, Scenery, Sports, Close-up, Night Portrait, and My Color modes. The My Color mode offers sub-options of Expressive, Retro, Pure, Elegant, Monochrome, Dynamic Art, Silhouette, and Custom, which lets you adjust Color (from red to blue), Brightness, and Saturation to your liking.

Panasonic G2 Movie-Mode Image Stabilization

Panasonic's image stabilization technology is lens-based, so IS effectiveness and impact on the audio track will depend on the lens you're using. We felt that the kit lens's IS worked well, and had relatively little impact on the audio, but we could definitely hear it working in quiet passages: When recording in quiet settings, you'll probably want to turn it off. We felt that it was a good bit quieter than Olympus' body-based IS system.

Panasonic G2 Video: Audio recording

Like most competing SLR/SLD cameras with video recording capability, the Panasonic G2 can record audio via its internal microphone. Unlike many competing models, though, it also includes an input jack for an external stereo microphone, hidden under a rubber flap on the left side of the body (as viewed from the rear). This is a big bonus for serious video users, as an external mic jack lets you avoid the inevitable noise on the audio track whenever you move your hands on the camera or actuate controls while recording. It also permits the use of things like a separate hand-held shotgun mic, a mic with a "dead kitten" wind filter, or a wireless mic system for truly professional audio recording. Panasonic themselves sell an external stereo mic (the DMW-MS1) that plugs into the G2's jack and mounts on the hot-shoe, but there are loads of third-party mic systems that should work just fine with the Lumix G2 as well. (One important note, though: The audio-in jack on the Panasonic G2 takes a 2.5mm plug, so you'll need an adapter to use mics with standard 3.5mm plugs on them.)

Panasonic doesn't publish specs for the G2's audio recording capability, so we don't know the sampling rate or number of bits of A/D resolution employed. Audio recorded with the camera's internal mic seemed plenty clear, but we do no tests to measure frequency response or sensitivity. We didn't have an opportunity to test with an external mic, so can't comment on the audio fidelity when recording from external devices. (We didn't have a 3.5/2.5mm adapter while we had the oval sample of the G2, so we couldn't test with our external Rode SVM mic or our AudioTechnica wireless rig.) We did notice that there was audible hiss in audio tracks recorded with the in-camera mic in very quiet environments. On a positive note, though, we didn't hear any audible "breathing" from the auto-gain system adjusting sensitivity as sound levels got louder or softer.

Given that we didn't test with an external mic, it's hard to say whether the audible hiss would be a factor in sound recorded from external sources, or if it's just a factor when working with the internal mic. We're inclined to suspect the latter, given that audio digitization isn't that challenging technically.

As noted, the Panasonic G2 doesn't have any provision for manual audio level control, whether working from the internal mic or an external audio source. This isn't a particular strike against the G2, though, as manual level control is a feature found on only a few digital SLRs, and those are well above the G2's price range. To sidestep this limitation, many amateur videographers simply use a separate, inexpensive digital audio recorder to record a separate soundtrack, which they then synchronize with the audio from the camera in their editing software. Software synchronization of audio tracks gives essentially perfect alignment of the video and externally-recorded video with relatively little effort.

Panasonic G2 Movie Recording User Interface

The Panasonic G2 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 on the camera's top panel, and the camera will start recording video. Video resolution and file format are available via the rear-panel LCD, whether in still or Motion Picture P mode (the dedicated movie recording mode), and you can change these settings at any time via the Quick Menu, using either the touch interface or physical buttons. The result is a camera that feels like it was intended to shoot video from the start, rather than one with movie recording grafted on as an afterthought. The quick access to video recording makes it much more likely that you'll use the Panasonic G2 to record little "video snapshots," rather than it being a big production to switch in and out of video mode.

As mentioned earlier, there is a specific mode dial option for movie recording, called "Motion Picture P" mode. (The icon is a movie camera with the letter "P" following it.) Given that you can initiate movie recording from any of the Panasonic G2's still-capture modes, a separate movie-recording mode seems a little redundant, but it perhaps makes the user interface surrounding the Peripheral Defocus function a little less confusing: In still-capture modes, the rear dial is used to control EV adjustment and either aperture, shutter speed, or both, so it might have been confusing to add Peripheral Defocus adjustment to the same control, when it would only apply to movie recording.

We've generally favored use of the shutter button to start and end video recording, but found ourselves really liking the convenience of the G2's dedicated record button. Having it on the top panel, right behind the shutter button also made it very quick to access with our index finger, so it was simply a matter of reaching back slightly to capture video vs a still image. The touch screen was also nicely integrated into the video recording interface; we found it especially handy for moving the focus point, and used the Quick Menu quite a bit for changing the video recording mode and/or resolution.

One thing to be aware of in recording movies directly from a still-capture mode is that the aspect ratio can change if the video and still-capture mode options are set differently. This can be a little disconcerting the first few times it happens. The solution is to either just learn to expect it, or to check ahead of time to see that you're using the same aspect ratio for both still and video capture.

A minor niggle we had with with the Panasonic G2's movie mode was that the Movie button required a rather deliberate press to either stop or start movie recording: Until we got used to it, we several times found the camera still recording video after we thought we'd stopped it. It wasn't a big deal, but we did feel we had to be very deliberate about pressing the Movie button to start/stop recording.

A much larger issue is that we discovered there to be a combination of significant lag and anticipation (for lack of a better word) when starting/stopping movie recording. When starting a recording, we found that the recording didn't start until about a second after pressing the Movie Record button. While we haven't tracked this "movie shutter lag" with other cameras, we've seen varying amounts of delay in the video-capable SLR/SLD cameras we've tested in this regard. Somewhat more disconcerting, though, was that our sample of the Panasonic G2 stopped recording early, with the end of the recorded video coming about a half-second before the point at which we'd pressed the Movie Record button to stop it. This was rather odd in our experience, and led to us chopping off a number of video clips short, ending them before we intended to.

Panasonic G2: 2MP Stills During Video
One of the Panasonic G2's more unusual features is its ability to capture up to 20 still images while a video is recording. Above is a reduced-size image of one such shot, captured during AVCHD video recording.
Here's a 1:1 crop from the shot shown above. These shots are only 2 megapixels (1,920 x 1,080), but they're plenty good enough for 4x6 inch prints.

One unusual feature of the Panasonic G2 is its ability to capture up to 20 still images while a video recording is ongoing, simply by pressing the shutter button whenever you want to grab a frame. Captured frames are held in the camera's memory until you're done recording, being saved to the memory card once the recording has finished. These in-movie still images are limited to 2-megapixel resolution, and the feature is only available when a movie recording is initiated from a still-image capture mode. (When you're in Movie-P mode, pressing the shutter button toggles the video recording. That is, it starts it if a movie isn't currently recording, or stops it if one is.) Simultaneous still/movie recording is also not available when the resolution is set to VGA or QVGA in Motion JPEG mode.

While the resolution of these in-movie still images is limited to 2 megapixels, what's nice is that grabbing them doesn't pause or otherwise interrupt the video recording. You will, however, very clearly hear clicks from the actuation of the shutter button in the movie's audio track. At only 2 megapixels, you won't be making posters with these shots, but there's plenty of resolution to make decent 4 x 6 inch prints. We found it very interesting to note that the resolution of these still images is actually 1,920 x 1,080 pixels, rather than the 1,280 x 720 maximum resolution of the Panasonic G2's recorded video. The obvious question is whether the G2's sensor might not actually be recording at 1,920 x 1,080, which is then reduced to the 720p resolution to ease video encoding. (Might there be a "GH2" coming in the near future, similar to the GH1 following the G1?)

Setting adjustments in movie mode are made via the Motion Picture Menu, which for convenience shares a few items with the main Record Menu. Here's a list of the options found on the Motion Picture Menu:

Motion Picture Menu Options:
Top-Level Selection	Second-Level	Notes
Rec Mode	- AVCHD Lite - Motion JPEG
Rec Quality	(AVCHD Lite mode) - SH - H - L (Motion JPEG mode) - HD - WVGA - VGA - QVGA	Two separate sets of options, depending on whether AVCHD Lite or Motion JPEG recording format is selected. (Note that WVGA isn't available in Intelligent Auto Mode.)
Continuous AF	- Off - On	Normally focuses continuously in video mode. If this setting is Off, AF occurs only when shutter button is pressed halfway. (Handy to prevent AF noise from affecting the audio track.)
Metering Mode	- Multiple Area - Center Weighted - Spot	Spot metering follows face of subject when Face Detect AF is selected, follows chosen AF point in Spot AF mode (NB: Shared with REC mode; changing here changes on REC mode screen also.)
iExposure	- Off - Low - Standard - High	Adjusts contrast and brightness to improve apparent dynamic range (range of light to dark values that can be recorded). (Also shared with REC mode screen.)
Wind Cut	- Off - Low - Standard - High	Processes audio being recorded to attempt to remove wind noise.
Ex. Opt. Zoom	- Off - On	Increases zoom by using only central pixels of sensor. Increases zoom 2x at lower resolution settings with still images, 3.1x when recording video at HD resolutions, or 4.2x when recording at VGA or QVGA video res. (Also shared with REC mode screen.)
Digital Zoom	- Off - 2x - 4x	Interpolates images to add constant 2x or 4x magnification, but with equivalent loss of image quality. Can be applied in combination with Ex. Opt. Zoom above. (Also shared with REC mode screen.)

Panasonic G2 Video Quality and Artifacts

We felt that the Panasonic G2's video quality was pretty comparable to that of its competitors, neither exceptionally better or worse than that of other models. As usual, the AVCHD Lite recording format provided a high-quality viewing experience with very small file sizes, but lost detail pretty dramatically when the camera was panning rapidly, or when there was a lot of rapid subject movement. In fairness, though, those times are exactly when our eyes will be less aware of fine detail, so its loss isn't as significant an issue as some of the freeze-frame crops below might suggest. Motion JPEG does much better with high levels of subject motion, but at the cost of files nearly twice as large. Overall, we felt the Panasonic G2 produced very good-quality 720p video. (While few people are likely to purchase a G2 expressly for recording VGA-resolution videos, it does deserve noting that its VGA video is , with lots of compression artifacts. Stick with its HD-resolution video and you'll be happy.)

Here are some examples of what we found in the Panasonic G2's movie files:

Panasonic G2 Video Quality Samples
AVCHD - SH mode	AVCHD - L mode
When there's little motion in the scene, AVCHD delivers excellent frame quality.	Even at the lowest-quality quality setting, the G2's AVCHD format offers very good detail.
AVCHD - SH mode	Motion JPEG - HD setting
When there's a lot of motion within the frame (such as when panning rapidly, as was the case here), the penalty for AVCHD's small file sizes becomes clear, in the form of significantly blurred detail. It's important to note, though, that we're pixel-peeping pretty badly here: When the whole frame is moving, our eyes aren't nearly as sensitive to finer details. The running video doesn't look nearly as blurred as we see here in this frame-grab crop.	All else being equal, the Panasonic G2's Motion JPEG files are almost twice the size of AVCHD ones, but they offer much less of an image quality penalty for rapid motion. This isn't a perfectly controlled test, but the rate of panning in the shot above was about the same as that in the AVCHD frame shown at left, and the difference in increased detail is very evident.
AVCHD - L mode	Motion JPEG - VGA setting
It's worth repeating again the notes above about single-frame crops from videos representing extreme pixel-peeping. That said, motion artifacts with the "L" (low quality) AVCHD option are pretty apparent, even when the video is rolling.	Motion JPEG doesn't automatically mean no artifacts, though: The Panasonic G2's VGA-resolution video (640x480) has pretty severe compression artifacts, whether the subject is moving or not. If you only want low-res videos for web use, you'd probably do better with a digicam...

Rolling Shutter Artifacts

Panasonic G2: Rolling Shutter Artifacts
While present, we found the Panasonic G2's rolling shutter artifacts to be less obtrusive than those of some of its competitors. The slanted verticals in the shot above show this effect.

Essentially every video capable digital SLR/SLD currently on the market exhibits motion-related distortions called rolling shutter artifacts. These are caused because the image data is captured and then read off the chip sequentially by rows, rather being captured all at once. In the case of the Panasonic, this means that image data for the last row of a given frame is captured and read out anywhere from 1/25th to 1/30th second after the data for the top row was captured. The effect on moving objects is similar to 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.

The specs for the Panasonic G2 indicate that it reads a frame of data from its sensor either every 1/30 second (for AVCHD NTSC mode, and all Motion JPEGs) or 1/25 second (in AVCHD PAL mode). These are fairly typical rates for cameras in this category, but we found the G2's rolling shutter artifacts less obvious than they are in some models. Perhaps some cameras actually capture all lines in the frame faster than 1/30 second, but simply take the full 1/30 second to read the data out? Whatever the case, this isn't a scientific test we're performing here, but it supports our general sense that the G2 did better in this respect than some models we've worked with.

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 Panasonic G2 supports both AVCHD and Motion JPEG recording formats. The AVCHD format is much more space-efficient on the memory card, and displays well on HD television sets, but is much harder for computers to decode. If most of your video playback will be on a computer, you may find Motion JPEG to be more to your liking. On the other hand, if your computer supports AVCHD fine, that would be the preferred format, given its space efficiency.

As of this writing (in late April, 2010), support for AVCHD on the Mac platform is terrible. The free VLC player program does a decent job, but is prone to motion artifacts. We're not aware of any other free player software for the Mac that does any better. Panasonic provides software for viewing and working with AVCHD video for the Windows platform, but not for Macs.

Panasonic G2 Video Mode: The Bottom Line

Overall, the Panasonic G2 is a great camera for consumers looking for a capable interchangeable-lens camera that can record video without the hassle of essentially manual focus. While not perfect, its live autofocus tracking during video recording is better than that of most SLRs and several competing SLD models. (We used it with its kit lens; lenses designed specifically for video focusing would likely do a good bit better.) When recording video, it lacks direct control over the aperture, shutter speed or ISO settings, but offers some control over depth of field via its Peripheral Defocus setting, and a limited selection of shutter speeds via its Flicker Reduction setting. Perhaps helped by the lower data rate requirements of its 720p (vs 1080i) video resolution, its video image quality was good, and relatively artifact-free. While it's not quite a tool for professional-grade video recording, advanced amateur users will applaud the external audio jack, which permits the use of external mic systems for higher-quality and better-controlled audio recording.

All in all, we had a very good experience with the Panasonic G2's video, and its smooth-working autofocus is just what the average consumer needs for hassle-free video recording.