Panasonic DMC-G2 Optics
Panasonic Lumix DMC-G2 Optics
Panasonic LUMIX G Lenses
The Panasonic G2 is compatible with any Micro Four Thirds lens, with Panasonic and Olympus together having shipped a total of nine lens models at the time of writing (April 2010). Three further Micro Four Thirds lenses have been announced, but have not yet reached the market. Panasonic has dubbed the bulk of their Micro Four Thirds lenses "LUMIX G," and the company has released seven models to date. Five of these are zooms, as identified by their Vario branding, while the remaining two are primes.
The Panasonic Lumix G Vario 7-14mm f/4.0 Asph is the company's widest zoom lens, offering a 35mm-equivalent range of 14-28mm. It's also the only non-stabilized zoom in Panasonic's lineup. The only other lens inside this range is the Lumix G 20mm f/1.7 Asph. prime. At just an inch long and 3.5 ounces, it's the smallest, lightest, and brightest of Panasonic's Micro Four Thirds lenses, and offers a 35mm equivalent focal length of 40mm. It's also one of only two primes the company offers, with the other not carrying Lumix G branding. Instead, it's branded as the Leica DG Vario-Elmarit 45mm f.28 Asph. Mega O.I.S. This is the only macro lens in the line, offering a maximum magnification of 1.0x -- far greater than the 0.2x magnification of the next nearest model, the 14-140mm (which we'll come to in a moment).
The Lumix G Vario 14-42mm f/3.5-5.6 Asph. Mega O.I.S that ships as a kit with the Panasonic G2 is the lightest zoom lens in the line, and offers equivalent focal lengths from 28-84mm. To save weight and cost, the 14-42mm lens forgoes an IS switch, with stabilization instead being enabled or disabled through the camera's menu system. It also uses a plastic lens mount, instead of a metal one. The Lumix G Vario 14-45mm f/3.5-5.6 Asph. Mega O.I.S. is just a fraction smaller and has ever so slightly more reach, with an equivalent range of 28-90mm, but weighs almost 20% more than the 14-42mm model. The Lumix G Vario HD 14-140mm f/4.0-5.8 Asph. Mega O.I.S. has by far the most reach of Panasonic's Micro Four Thirds lenses, with 35mm-equivalent focal lengths ranging from 28-280mm. It's the only lens carrying the "HD" badge, which indicates that it's designed for movie recording. This comes thanks to two specific features -- a nearly silent inner focus direct-drive linear motor for continuous auto focusing, and a seamless aperture adjustment. Not surprisingly, it's the heaviest of the group, at just a hair over a pound, although it's not the largest. That honor goes to the Lumix G Vario 45-200mm f/4.0-5.6 Mega O.I.S., which is just under four inches in length, with a diameter of 2.75 inches.
We've shot extensively with Panasonic lenses as part of our reviews of Panasonic cameras, and have also tested them in the lab for SLRgear. Overall, we've found Panasonic's lenses generally to be of very good quality. Helped in part by in-camera processing which reduces both geometric distortion and chromatic aberration, Panasonic lenses have consistently delivered excellent optical results in our testing and use. Lens quality is an important part of the decision whether or not to adopt a new camera system, and on that score, the Panasonic G-series does very well.
Further options are available from Olympus, Panasonic's partner in the Micro Four Thirds format, which currently offers two Micro Four Thirds-mount lenses, and has two more nearing release, for a total of three zooms and one prime. One third party -- a new startup company called Noktor -- has also announced a completely manual, Micro Four Thirds compatible 50mm F0.95 prime lens which seems to be based on a design intended for CCTV security cameras.
The Micro Four Thirds mount has an unusually small flange to sensor distance, which means there's plenty of room to insert mount adapters between the camera body and lens flange. As a result, no less than nine different adapters make it possible to mount a wide selection of current and historic glass on a Micro Four Thirds camera. Lenses that can be adapted include certain standard Four Thirds, Panasonic OM, Leica M / R, Voigtlander VM / Ai-S / PK-A/R / KA, and Carl Zeiss ZM / ZF / ZK types. These adapters generally have some limitations as to compatibility and available features, which will depend on the specific model being used, but the Micro Four Thirds platform is nonetheless unmatched in terms of compatibility with other lens mounts.
Because the company's lenses largely feature optical stabilization, the Panasonic G2 doesn't itself incorporate in-body image stabilization. This means that while third party lenses can be used with the camera, only Panasonic's lenses offer stabilization on the G2 (at least, for the time being -- it's certainly possible that a third party could offer its own stabilized Micro Four Thirds lens in the future).
Panasonic G2 Autofocus
The Panasonic G2 has a 23-area contrast-detect autofocus system, using the main imaging sensor to determine focus, similar to how most point & shoot cameras work. There are four AF Area options, selected by rotating the AF Mode dial -- Face Detection, AF Tracking, 23-area Focusing, and 1-area Focusing. In addition, there are three focus servo modes, selected with the Focus Mode lever that encircles the base of the AF Mode dial. These are Single AF (AFS), Continuous AF (AFC), and Manual.
A built-in AF Assist lamp illuminates the center of the image frame in difficult lighting conditions, to assist in achieving a focus lock. Its effective range varies depending on the lens in use, and it can be disabled altogether for situations when it might prove a distraction to your subject, or otherwise objectionable. Lenses with larger diameters may partially or completely block the assist lamp from illuminating your subject.
When the AF Mode dial is set to the Face Detection mode, the camera automatically detects up to 15 faces in a scene, and can be programmed to recognize three specific individuals whenever they appear in the frame, allowing them to be prioritized over other faces when recognized. (In other words, you can train the camera to distinguish three specific people from others, and base exposure and focus on just their faces, rather than others in the frame.) The G2 will focus on an individual selected by the face recognition function if possible, or on the dominant face if no individuals are recognized. When a photo contains more than one recognized face, the camera selects on which face to focus based on the priority selected when programming the faces to be recognized. There's also a three-step control over the facial recognition sensitivity, allowing higher recognition accuracy (but with an increased likelihood that one of the designated faces won't be recognized), or vice versa.
The face selected for focusing is indicated by a yellow frame until focus lock is achieved, at which point the frame color changes to green; other faces get a white frame to indicate their location. Once detected, faces are tracked around the screen automatically. A manual AF point can be set in face detection mode by simply touching the desired point on the screen, and one of four point sizes selected by dragging a slider that appears at the right-hand side. The point position can also be set or adjusted with the arrow buttons on the back of the camera, and the size adjusted by rolling the rear dial. If a manual point is set, all detected faces are still indicated with white frames, but not used for AF calculation.
The AF Tracking mode is great for shooting sports, kids, and pets, as it automatically tracks any moving subject -- not just faces -- around the frame, based on the subject's tone and color. The subject can be selected by touching it on the screen. Alternatively, it can be selected by aiming the camera so as to place the AF point over the subject, then half-pressing the shutter button. In either case, when tracking, the subject is indicated with a yellow frame. Face recognition is disabled when the camera is set to AF tracking mode. The tracking mode also doesn't function when the Panasonic G2 is set to black & white film modes, or the monochrome My Color mode.
In 23-Area Focusing mode, the G2 automatically selects between all twenty three focusing points by default. By touching the screen, one of nine groups of AF points can be selected, and the camera will automatically choose only from the points in the selected group. Each group consists of five points, apart from in the extreme corners of the frame, where the groups only contain four points. The selected group is indicated by a cross mark in the center of the cluster of AF points, and it's also possible to select the group without using the touch screen by holding the Q.Menu button until the selection screen appears, then using the arrow buttons or rolling the rear dial to make the selection.
Finally, the 1-Area Focusing mode provides a single autofocus point which can be moved anywhere within the frame except the extreme edges, again either by touching the display or by using the arrow buttons. As with the face detection mode, the AF frame size can be changed to Spot, Normal, Large or Extra Large, either by dragging an on-screen slider, or by rolling the rear dial.
In Single AF servo mode, the camera will attempt to determine the point of focus when the shutter button is half-pressed, and then lock focus at this distance for as long as the shutter button remains pressed. Two Custom menu settings allow AF lock to alternately be assigned to the AF/AE Lock button -- either while held in, or when pressed once, with a second press releasing the lock. A further Custom setting instructs the camera to operate in AF+MF mode, allowing the point of focus to be fine-tuned manually after the autofocus operation is complete.
In Continuous AF servo mode, the camera will attempt to predict subject motion and keep the area under the AF point in focus, for as long as the shutter button remains half-pressed. Because contrast-detect AF systems have to perturb the focus in order to tell whether the image is actually in focus or not, the DMC-G2's Continuous-AF mode's operation can be seen in the viewfinder, at least if you're watching closely: The viewfinder image will continuously very slightly in and out of focus when C-AF is active, as the camera constantly re-checks its focus setting.
A Focus Priority setting in the Custom menu allows the Panasonic G2 to be set to require a focus lock before the shutter can be triggered, or alternatively to allow the shutter to fire regardless of whether a lock has been achieved. When shooting in burst mode with continuous AF, enabling Focus Priority can reduce the burst speed, because a focus lock must be obtained before each shot in the burst. With Focus Priority disabled, the G2 simply focuses at the predicted distance for each subsequent image in the burst, without actually confirming a focus lock has been achieved. (For bursts in Single AF mode, focus is locked from the first shot, so the only effect enabling Focus Priority has in this situation is that it delays firing of the first frame in the burst, until a focus lock has been achieved.)
Through another Custom menu setting, the Panasonic G2 can be configured to attempt to achieve a focus lock in AF-C mode before the shutter button is half-pressed. When this Pre-AF setting is set to Continuous AF (C-AF), the camera will seek a focus lock at all times. Alternatively, when set to Quick AF (Q-AF), the G2 will begin seeking a focus lock as soon as the camera is held relatively steady. With either option set, the time to obtain an AF lock should be reduced, but at the expense of battery life.
Of course, the Panasonic DMC-G2 also offers a Manual Focus mode. In MF mode, a Custom setting called MF Assist optionally causes the camera to magnify the preview image by 5x, whenever the focus ring is adjusted, to help determine critical focus. The MF assist preview can be panned around the image frame by dragging your finger across the surface of the display, and the zoom level increased to 10x (and reverted to 5x) by pressing an on-screen magnifying glass icon. After 10 seconds of manual focus inactivity, the Panasonic G2 reverts to showing the full image frame.
For use with old manual-focus lenses (which lack the communication that would tell the body when the focus ring was being adjusted), or perhaps to simply check the focus that the AF system has achieved, it's also possible to call up the MF assist function without first adjusting focus, either by touching the display when in MF mode, or by holding the Q.Menu button briefly. When the latter method is used, the arrow buttons will pan the zoomed preview, and the rear dial will switch between 5x and 10x zoom levels. An MF Guide function displays an on-screen gauge with a visual indication of the current relative focus distance, making it easy to see whether you're focusing closer or further away when the focus ring is turned. (It doesn't display the actual focus distance, just a relative range from close-up to infinity.)
While the LCD on the Panasonic G2 is a relatively high-resolution design, with some 460K dots, it still lags behind the extremely high 1,440K dot resolution (800 x 600 pixels x three dots per color) of the electronic viewfinder. For precise manual focusing, the EVF hence proves a better choice.
In the above discussion, we mentioned several times how the Panasonic G2's touch screen can be used to set the AF point, identify the desired subject, or call up the focus-assist display in Manual Focus mode. We've often said that we're no particular fans of touch-screen interfaces, but the touch interface on the Panasonic G2 really made believers of us. Shawn and Dave both remember first hearing about it in the non-disclosure briefing for the G2, and thinking "eh - another gimmicky touch-screen interface." Once we had a chance to shoot with the camera, we found our opinion changing pretty radically: The touch interface on the G2 is really done exactly right, and using it to set focus or select a subject for tracking is an incredibly natural way of doing so. Perhaps the best measure of how much we liked it is how often we find ourselves wanting to select an AF point on other cameras we're testing by poking their screens.
Shawn made a little video showing how the Panasonic G2's touch interface works. It was linked on the first page of this review, but the touch interface is such an integral part of the G2 experience that we felt it was worth re-linking here. Check it out, it's really a whole new way of relating to your camera!
AF in Movie mode
In Movie mode, you have the same focusing options available as when shooting stills, and it is possible to adjust focus not only before movie recording starts, but also during recording. There
are a couple of differences from their still image counterparts though -- the most
obvious being the absence of the beep that serves to confirm AF lock. Also, when set to AF-C servo mode on the Focus Mode lever, the Panasonic G2 looks to a setting in the Motion Picture menu to determine whether to allow Continuous AF. If the option is disabled, the G2 will operate in Single AF mode, regardless of the Focus Mode lever being set to AF-C, performing an AF operation only until a lock is achieved. If the option is enabled, Continuous AF becomes available during movie recording as well as for still images. Since focus operation is picked up by the camera's internal
microphone, you may want to choose either S-AF or MF modes to minimize
the impact of the focus motor noises. It's also important to note that even when in MF mode, focus operation can result in motor noise being picked up on the audio track, since most Micro Four Thirds lenses use a fly-by-wire system for manual focusing, rather than a direct mechanical linkage. The extent to which AF noise is recorded on the audio track will vary depending on the specific lens used.
Panasonic DMC-G2 Sensor Cleaning
The Panasonic DMC-G2 features an ultrasonic dust-reduction system, especially important since the DMC-G2's shutter is normally open for full-time Live View. The system automatically runs at power-up, and might as a result slow camera startup slightly. We measured the G2's delay from power-on to first shot at about a second, which is slower than some competing SLR models. That said, we never felt that the G2's startup time was too slow, or came even close to causing us to miss a shot.
We have found, however, that in-camera dust-removal systems are less than perfectly effective. You're still going to need to use a sensor-cleaning kit fairly often, so the advantage of in-body dust removal is perhaps less than it might seem. If you've got dust specks on your sensor (and sooner or later you will), you're going to need to clean it. There are a lot of products out there intended to address this need, but a distressing number of them work poorly (if at all), and many are grossly overpriced. Advertising hype is rampant, with bogus pseudo-scientific jargon and absurd product claims. And prices -- Did I mention prices? How about $100 for a simple synthetic-bristle brush?
So how do you know what product to use?
We don't pretend to have used everything currently on the market, but we can tell you about one solution that worked very well for us. The "Copper Hill" cleaning method is straightforward and safe, and in our routine usage here at Imaging Resource, highly effective. Better yet, the products sold by Copper Hill Imaging are very reasonably priced. Best of all, Nicholas R (proprietor of Copper Hill) has put together an amazingly detailed tutorial on sensor cleaning, free for all.
Sensor cleaning is one of the last things people think about when buying a d-SLR, but it's vital to capturing the best possible images. Take our advice and order a cleaning kit from Copper Hill right along with your d-SLR, so you'll have it close at hand when you need it: You'll be glad you did!
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Kit Lens Test Results
Very good performance with the 14-42mm OIS kit lens.
|14mm @ f/8||26mm @ f/8|
|42mm @ f/8||4x Digital Zoom|
The Panasonic G2 is available bundled with a Lumix G 14-42mm f/3.5-5.6 OIS Micro Four Thirds lens. The kit lens possesses a typical optical zoom range of 3x, and the 35mm equivalent focal range is about 28-84mm, a result of the G2's 2x "crop factor." Results were very good at 14mm, with strong detail throughout most of the frame and only slightly soft corners. Coma distortion in the trees was low, but some minor to moderate chromatic aberration can be seen near the edges. Results were very good at the 42mm setting, though corners were also a bit soft. Chromatic aberration at full telephoto was negligible. The lens also performed well at the intermediate focal length of 26mm. The Panasonic G2 offers up to 4x digital zoom with the typical loss of fine detail you'd expect for that amount of digital magnification. Overall, a very good result for a kit lens, and the built-in optical image stabilization should come in handy with hand-held shots in poor lighting conditions.
A larger than average area (for an SLD* kit lens), with good but slightly soft detail. Flash did a good job throttling down, though.
14-42mm kit lens
|Macro with Flash|
As with zoom performance, the Panasonic G2's macro performance will depend entirely on the lens in use. However, with the 14-42mm kit lens set to 42mm, the Panasonic G2 captured a larger than average minimum area measuring 3.75 x 2.81 inches (95 x 71 millimeters). Detail was good with just a hint of softness. There was only a small amount of blurring in the extreme corners. (Most lenses have some softening in the corners at macro distances, the Panasonic G2's kit lens has far less than most.) The built-in flash did a good job throttling down at such a close distance resulting in a well-exposed image, though there was slight light falloff toward the bottom of the frame.
*SLD = Single Lens Direct-view
Low geometric distortion with the 14-42mm kit lens in JPEGs, much higher than average distortion at wide angle in uncorrected RAW files.
|In-Camera JPEG: Barrel distortion at 14mm is 0.3 percent|
|In-Camera JPEG: Pincushion distortion at 42mm is 0.3%|
|Uncorrected RAW: Barrel distortion at 14mm is 1.9%|
|Uncorrected RAW: Pincushion distortion at 42mm is 0.3%|
When shooting JPEGs, the Panasonic G2's 14-42mm kit lens produced about 0.3 percent barrel distortion at wide-angle, which is much less than average and hardly noticeable in its images. At the telephoto end, there's about 0.3% pincushion distortion, also not very noticeable. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).
To see how much correction is taking place in the camera, we converted RAW files from the above shots with dcraw, which does not correct for distortion. As you can see, at wide angle, the barrel distortion is very high at about 1.9%, while pincushion distortion at the telephoto end remained the same at about 0.3%. We expect this for smaller interchangeable lenses though, so it's nothing to be concerned about unless you are using a RAW converter which does not understand the embedded "opcodes" to perform distortion corrections automatically. Most RAW converters these days are capable of applying distortion correction automatically, as specified by the manufacturer. (There's going to be some loss of resolution as a result of such correction, because pixels in the corners of the frame are being "stretched" to correct for the distortion. Obviously, a lens that doesn't require such correction, and is also sharp in the corners to begin with would be preferable, but relaxing constraints on barrel and pincushion distortion likely brings other benefits in the lens design.)
Chromatic Aberration and Corner Sharpness
Fairly low levels of chromatic aberration from the 14-42mm kit lens in JPEGs. RAW files show moderate amounts. Some soft corners.
|Wide: Upper left
C.A.: Moderately low
Softness: Moderate blurring
C.A.: Very low
Softness: Very Sharp
|Tele: Upper right
C.A.: Moderately low
Softness: Moderate blurring
C.A.: Very low
Chromatic Aberration. Chromatic aberration in the corners with the Panasonic G2's 14-42mm kit lens is quite low and dull at wide-angle (14mm). At full telephoto (42mm), C.A. is also moderately low. The camera does a pretty good job of removing it from JPEGs. As usual, what little color fringing there is gradually reduces in brightness and width as it approaches the center of the image, where it is nonexistent.
Corner Softness. The Panasonic G2's 14-42mm kit lens produced some soft corners in a few shots. At full wide-angle, the left corners were slightly softer than the right. Blurring extended fairly far into the frame. There's no doubt that the geometric distortion correction that is being applied contributes to the corner softness at wide-angle. At full telephoto, the right corners were a bit softer than the left. The center was sharp, but had lower contrast than at full wide-angle. Overall, a good performance for a kit lens here, especially considering the lens was wide-open for these shots. (Corner sharpness generally improves when a lens is "stopped-down" a couple of f-stops below full aperture.)
|Wide: Camera JPEG||Wide: Uncorrected RAW|
|Tele: Camera JPEG||Tele: Uncorrected RAW|
Chromatic Aberration Correction. As mentioned above, the Panasonic G2 applies chromatic aberration correction to its JPEGs, as uncorrected RAW files show moderately higher levels. RAW files converted with Adobe Camera Raw are also automatically corrected, so we used dcraw for the uncorrected conversions on the right.
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Panasonic Lumix DMC-G2 Photo Gallery .
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