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Flash

The built-in flash of the Panasonic Lumix DMC-GX1 has a guide number of 7.6m at ISO 160.

As you'd expect in a pop-up flash of this size, you'll need to be fairly close to your subject for best results. The GX1 does offer flash exposure compensation of +/-2 stops EV.

As with many small pop-up flash units, photographing a subject with the GX1 from a close distance can produce harsh shadows. Although not designed intentionally for such use (so do this at your own risk), the GX1's built-in flash unit can be manually positioned to bounce flash for a more diffuse light. In each of the examples shown below, the camera was set to Program mode with an exposure of 1/60 at f/4.6 at ISO 800.

In its default, open position (shown inset), the GX1's flash unit employs a double-hinged design to extend forward from the camera, sitting approximately two inches above the center of the lens.

At a camera to subject distance of just under six feet, the flash can produce a harsh shadow.

The flash can be pulled back and locked into its housing cavity with the flash head pointing straight up to bounce off of the ceiling.

Bouncing the flash eliminates the shadow behind the subject but the flash itself has too little power to bounce off of a high ceiling and still provide much illumination.

With the flash in its bounce position you can easily use a business card to redirect the light towards the subject. This results is a softer shadow than in the first example, but with more illumination reaching the subject than in the second example.

iDynamic mode

The GX1, like its G-series predecessors, offers a range of three iDynamic settings - Low, Standard and High - which are meant to be used in high contrast situations, ostensibly to enhance the dynamic range. At a given setting, the camera analyzes the scene to determine what adjustments are necessary. As we note on our dynamic range page of this review, our studio test scene triggers no meaningful response in any of the iDynamic settings. In real-world scenes of very high contrast, the effect is rather subtle even with iDynamic configured to its strongest setting. Shadows are brightened (and thus display slightly more visible chroma noise) yet highlight detail remains essentially unchanged.

This image was shot with iDynamic mode turned off. Setting iDynamic to 'high' - its strongest setting - slightly increases brightness in the shadows.
In these 100% percent crops it's clear that the bright highlights shown above with iDynamic disabled... ...do not show significantly greater detail with iDynamic enabled, even at its strongest setting.
This 100% crop shows shadow areas as rendered with iDynamic turned off. With iDynamic set to 'high', the shadows are brightened which does make chroma noise slightly more apparent.

The overall effect of iDynamic is akin to applying a low-contrast curve adjustment in Photoshop, in which the shadows are lifted slightly while the midtones and highlights remain largely unaffected. While there's no performance penalty incurred by simply turning iDynamic on and getting a slight benefit of brighter shadows in high contrast situations, this functionality lags noticeably behind competitive systems like Sony's DRO and Olympus' Gradation function, which actually serve to expand the default dynamic range, rather than simply reduce contrast.

White balance and skin tones

As we noted in our review of the G3, Panasonic has significantly improved some shortcomings regarding its white balance performance, particularly with regard to skin tones. For GF1 owners considering an upgrade to the GX1, it's useful to compare in-camera JPEG results with both cameras set to AWB in aperture priority mode and at the default 'standard' photo style/film mode.

As the samples below clearly demonstrate, the GX1 inherits this improved ability to render more realistic portraits. Caucasian skin tones, while perhaps erring a shade too far along the warm spectrum in the GX1, no longer exhibit the sickly green skin tone for which the GF1 has been criticized.

Panasonic GX1, ISO 200, 1/125 sec f/4 Panasonic GF1, ISO 200, 1/160 sec f/4

With this improved skin tone rendering, GX1 users can shoot portraits in JPEG format and end up with perfectly acceptable images. The GX1 has a 'portrait' photo style which, in some cases may produce a slightly more neutral skin tone, but as we noted in our review of the G3, this does not always produce more pleasing results. Yet there's no escaping the conclusion that the GX1's white balance rendering is clearly superior to that of first-generation G-series cameras. We can imagine that this alone may go a long way towards making the GX1 (or the G3) a compelling upgrade for GF1 owners.

Vignetting correction

Panasonic offers a shading compensation feature in its Record menu that corrects for lens vignetting. The following shading compensation analysis was shot using the Panasonic Leica Summilux DG 25mm F1.4, at its widest aperture. As you can see in the samples below the compensation function does reduce vignetting to a substantial degree. Perhaps most interesting is that this compensation is evident not just with in-camera JPEGS but on Raw files converted using Adobe Camera Raw. Adobe tells us they are not applying any vignetting correction to the Raw files and we also see this compensation in Raw files processed via dcraw, both of which strongly suggest that shading compensation is written into the Raw data before the file is saved.

Off (JPEG) On (JPEG) Off (Raw +ACR) On (Raw + ACR)

From these results we estimate falloff at 25mm F/1.4 to be approximately 1 1/3 stop EV, falling to about 2/3 stop EV when compensation is enabled.

Raw mode advantages

Shooting in raw mode offers a wide range of advantages. You can make after-the-fact adjustments to white balance, exposure, contrast and sharpening without further degrading what is already compressed image data from a camera-processed JPEG. Even if you are satisfied with your camera's default settings in these regards, one area in which raw file processing software such as Adobe Camera Raw (ACR) provides clear benefit is in noise reduction of high ISO images.

In the samples below we compare the GX1's default in-camera sharpening and noise reduction settings with the same image processed as a Raw file using ACR 6.6.

Camera JPEG (default parameters) Raw + ACR (default sharpening)
Luminance 24, Luminance Detail 50,
Color 61, Color Detail 35
As you can see in the 100% crops above, ACR adjustments to luminance and chroma noise reduction can be made while avoiding the detail smearing and color artifacts that are present in the camera-generated JPEGs.

While you can of course, adjust the GX1's in-camera noise reduction and sharpening settings, they are no substitute for the range of granular control that is available in ACR, or indeed most any Raw image converter.

RAW files for download

Don't just take our word for it - take a look at the GX1's raw files for yourself, and run them through your own software and preferred conversion settings. Here, we provide you with a selection of raw files of 'real world' scenes, and if you want to take a closer look at the GX1's studio scene shots, you can download original raw files from our Compared to (RAW) page.

Overall image quality

Like the G3, the GX1 uses Panasonic's latest generation 16MP sensor. And while its core image quality is essentially identical to the G3 in every regard, the GX1 does offer minor improvements to high ISO JPEG image quality. As we saw when the G3 was released, the GX1's JPEG color rendering, particularly with skin tones is much improved over that of first and second generation G-series cameras. Users moving to the GX1 from the GF1 in particular, will notice a substantial improvement in white balance rendering as well as the benefits of increased resolution and high ISO performance.

Continuing in the tradition of previous G-series cameras, the GX1's metering system works very hard to avoid highlight clipping. We would prefer to see this (overly) conservative approach to maintaining highlight detail made obsolete by the inclusion of dynamic range modes that have a meaningful impact on highlight detail retention. As it stands, there will be times that the camera-suggested exposure produces an image that is slightly too dark. We recognize, however, that it is very easy to access and adjust exposure compensation via the clickable thumb dial.

PZ 14-42mm kit lens: Issues

As has been reported by Panasonic owners in our user forums, the Lumix G X Vario PZ 14-42mm kit lens produces noticeably blurrier images at its long end than it does at wide and medium focal lengths. Interestingly, this issue appears only at shutter speeds between 1/60 sec to 1/200 sec, which suggests a vibration-induced issue rather than a problem of focus. We see only marginally different results with IS active versus disabled. Yet, to the extent that we do find differences, leaving IS on actually produces slightly more blur at these shutter speeds.

In the samples below we compare the GX1's power zoom lens against the Lumix G Vario 14-42mm standard kit zoom. The images were shot at identical focal lengths and exposure settings, mounted on a tripod with IS disabled.

14-42mm power zoom at 42mm
ISO 160, 1/80 sec f/6.3
14-42mm standard zoom at 42mm
ISO 160, 1/80 sec f/6.3

We've seen this behavior with multiple copies of the lens, using the current firmware (v1.1) and have been in contact with Panasonic concerning the issue. We will continue to investigate the problem and will update this review should any further information come to light. With such a pronounced and repeatable difference between both kit lenses under identical test conditions, we have a difficult time recommending the more expensive power zoom model for stills-oriented GX1 users.

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Comments

reanim888

Iam really like the design of the GX1, though I do have a few quibbles. It's a little bigger than the rest of the field, but none of these is sufficiently small with a lens attached to be considered significantly smaller than the others. It's got a nice-size grip and thumb rest, which makes it comfortable to hold and shoot single-handed, and it feels well constructed.

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