Panasonic DMC-G1

Noise
Film photographers had to deal with grain, the tiny speckles caused by inconsistencies in film emulsions. Oddly enough, digital photographers face an effect with a different cause but a similar appearance. It's called image noise, the visual blips and speckles caused by random electrical signals. The amount of noise varies from camera to camera, due to the inherent qualities of the sensor and other electronics used and the success or failure of the built-in noise reduction software used to tame the beast. We test by shooting a well-lit color chart for the full range of ISO settings, at all noise reduction settings provided. For the G1 there are five levels, ranging from -2 (the lowest noise reduction effect, but still not off entirely) through +2, the most aggressive setting. Hence the attractive five-line colored chart you'll find below.

Noise – Manual ISO (7.40)
Image noise is a problem area for the G1. It starts fairly high at nearly 1% across the board, and rises rapidly, becoming a true eyesore if you shoot at the two highest ISO settings. On the plus side, the different levels of noise reduction perform well, producing roughly a 20% improvement from minimum to maximum noise reduction setting. Still, the overall results here are mediocre.

The G1 earns a middle-of-the-pack score when evaluating image noise, with other cameras in the same price range offering significantly better performance.

Auto Noise (4.09)
Our noise testing for cameras on the Automatic setting is more a challenge to a camera's digital brain than its sensor. When set to Auto mode, it's up to the camera to evaluate the lighting situation and choose an appropriate ISO setting. Since image noise rises as ISO sensitivity climbs, choosing a high ISO to shoot in our well-lit lab is a no-no, and a poor score is the result. In this case, though, the G1 chose to shoot at ISO 250, which is a reasonable setting. While the Nikon D90 and Olympus E-520 stumbled by choosing too high an ISO setting, the mediocre score for the G1 results from the camera's relatively poor underlying noise performance.

Low Light (8.77)
The ability to take high-quality photos in available light, whether outdoors at night or indoors without flash, is a key differentiating point between current camera models. The megapixel wars may be over, but the flash-free photo fracas remains. And we found the Lumix G1 a worthy contender in this arena.

We test two different low-light scenarios. First, we light our standard color chart at four different levels, ranging from 60 lux (roughly what you'd find in a reasonably lit home) down to 5 lux, about what a single candle provides, shoot it at a consistent ISO 1600 and use Imatest to analyze both the color accuracy and image noise in the resulting photos. Shown below are thumbnails of the now-familiar Imatest output chart, contrasting what the camera captured in the outer rectangular bands with the original GretagMacbeth chart colors in the center.

Low Light Tests
60 Lux	30 Lux
15 Lux	5 Lux

Noise in these images is rather high, at nearly 2.5% at each lighting level, but the color accuracy was quite good for photos shot in dim environments, so overall the G1 scored well in our light level testing.

Next up is the long exposure test, analyzing image noise performance with extended shutter speeds (from 1 second out to 30 seconds). There are a few noteworthy findings here. One, while noise is fairly high at about 1.65% even at 1 second, it stayed nearly flat across the testing sequence. Second, while we used high ISO noise reduction in our other tests, here we compare performance with and without long exposure noise reduction, a separate camera setting. In this scenario, the camera's attempts to minimize noise actually worsened the problem, though only by an inconsequential amount. Long exposure noise reduction takes two exposures, one with the shutter open, a second with the shutter closed in an attempt to replicate the noise produced during the first exposure, and then mathematically subtract it. Considering the fact that most image noise is produced randomly, though, it's easy to see why this approach is generally ineffective.

We combine the camera's performance on both of these low light tests to produce an overall score for the section. The G1 did very well here, essentially on a par with the Canon (known for its low-noise performance) and bettering both Nikons, including the far more expensive D90.

Panasonic Lumix G1 Low Light Scores

Still Life
For every review we shoot two still life setups, one with our happy mannequin couple relaxing on the couch, the other with Rosie the Riveter and her miniature friends in a colorful tableau, at the full range of camera ISO settings. The lighting is fluorescent, the camera settings automatic. Clicking on the thumbnails below opens up full-size versions for your perusal (though with 12-megapixel files, the downloads can take a while). Use these images to judge the effect of escalating ISOs on image quality. Compare them with the images produced with other cameras we've reviewed. Print your favorites and trade them with your friends.

ISO 100
ISO 200
ISO 400
ISO 800
ISO 1600
Hi ISO (3200)