Image Quality and Performance

With a Snapdragon S801 system chip and 2GB of RAM DMC-CM1 features the same processor specification as many 2014 high-end smartphones. So it's not a surprise the Panasonic device always feels snappy and responsive in general use, for example when using a web browser or image editing app.

When you hit the camera icon on the home screen or pull the camera lever the lens has to slightly extend before the CM1 is ready for image capture. This means that at approximately two seconds camera start-up is a touch slower than the fastest models but by no means too slow. The camera lever also allows you to already turn the camera on while the device is still in your pocket, meaning it's ready to shoot once you're framing the shot. The camera is usually responsive in operation but the 20MP files take a moment to process and save. If you're shooting Fine quality and Raw files you'll have to wait more than three seconds between shots. It's only a second or so without the Raw file but still noticeably slower than on more conventional smartphone cameras.

In AF-mode the CM1 is continuously focusing which means by the time you half-press the shutter button to lock onto your subject focus is usually already pretty close. Fine adjustment takes only around a second. AF slows down in low light, but only slightly, and even in very dim conditions the CM1 can still reliably focus. However, one thing to keep in mind, especially for those photographers coming from more conventional smartphones, is that due to the Panasonic's larger sensor depth-of-field is shallower than on smartphone cameras with smaller sensors. On the plus side this means that you can use focus and sharpness as an additional creative tool. On the downside you'll have to make sure to place the focus in the right spot, otherwise you can end up with blurry subjects.

Daylight, Low ISO

In bright light, and when shooting in the standard color mode, the Panasonic Lumix DMC-CM1 images show colors that are more natural than most smartphones, with slightly less saturation and contrast. This is great for all those who prefer things close to reality or want some flexibility in post processing. However, if you want your images to 'pop', you can simply switch to the 'Vivid' color mode. Exposure tends to be good but occasionally 1/3 of a stop negative exposure compensation helps avoid clipped highlights in brighter parts of the scene. That said, with exposure adjusted accordingly the CM1 is noticeably less prone to highlight clipping than most of its smartphone competitors.

At the center of the frame detail is excellent, with just the right amount of sharpening. Fine low-contrast detail and textures are rendered smoothly and without any nasty processing artifacts. At F2.8 there is some noticeable corner softness. It improves as you stop down though and pretty much disappears at F5.6. Some luminance noise is visible in areas of plain color but it is very finely grained and less intrusive than on most smartphones. Traces of chromatic aberrations are visible on extreme high-contrast edges but overall it's not something you need to worry about in normal photography.

As mentioned above, those mobile photographers who are used to the almost infinite depth-of-field of smartphone cameras with smaller sensors need to slightly adjust their focusing habits for optimum sharpness and detail. Nevertheless the DMC-CM1 produces the best bright light image results of all current smartphone cameras.

ISO 125, F4, 1/800 sec 
Detail at the center of the frame is excellent.
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ISO 125, F4, 1/125 sec
With face detection enabled skin tones and exposure are very good.
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ISO 125, F4, 1/1000 sec
The 1-inch sensor allows for some blurring of backgrounds.
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ISO 125, F2.8, 1/100 sec
Finely grained luminance noise is visible in areas of plain color.
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ISO 125, F4, 1/640 sec
This image would benefit from a slightly darker exposure.
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Low Light, High ISO

While the CM1's bright light performance is excellent, it is in low light where the Panasonic hybrid camera, in comparison to its smartphone rivals, really shines. Luminance noise and some chroma noise appear early on and increase as you go up the ISO scale, but noise maintains a fine grain up to very high ISO levels. It's also much less intrusive than the smeared noise 'blobs' that we see on the high-ISO pictures of most small-sensor smartphone cameras. 

Even with the Panasonic's 1-inch sensor finer detail starts suffering noticeably from ISO 1000 upwards but edge detail is well maintained up to the the highest settings. There is no doubt that if image detail in low light is a priority, the Panasonic CM1 is currently the top choice among smartphones. Dynamic range is also well maintained throughout the ISO range.

However, there are a couple of points of criticism we'd like to make. We found the auto white balance system to be a little inconsistent in low light. A few times we took two images of the same scene within seconds of each other and had two quite different white balance results. In its auto exposure mode the CM1 also selected shutter speeds as low as 1/13 sec. Without an optical image stabilization system on board this greatly increases the risk of image blur through camera shake and we found quite a few photos with a slight blur among our high ISO samples. Luckily, the CM1's extensive manual controls allow for easy modification of image parameters which makes the latter less of an issue.   

ISO 160, F2.8, 1/60 sec
For bright indoor scenes ISO is only lifted slightly.
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ISO 400, F2.8, 1/30 sec
Traces of chroma noise appearing shadows.
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ISO 800, F2.8, 1/30 sec
Still decent textures at ISO 800.
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ISO 1250, F2.8, 1/60 sec
Fine detail noticeably starts suffering at ISO 1250.
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ISO 3200, F2.8, 1/80 sec
Lack of textures but still good edge definition at ISO 3200.
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By default the CM1 lets you choose ISO settings up to a value of 12800. If you enable extended ISO this goes up to 25800. Noise and the effects of noise reduction clearly take a turn for the worse at ISO 12800. The highest two settings are best reserved for emergency situations, but if you can live with the reduced pixel-level image quality they offer a good option for using faster shutter speeds even in pretty dim conditions.  

ISO 6400, F3.2, 1/125 sec
Dynamic range is maintained well at high ISOs.
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ISO 12800, F4, 1/160 sec
Lots of noise but this image is still usable at smaller viewing sizes.
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ISO 25600, F2.8, 1/125 sec
Significantly reduced detail at the maximum ISO setting
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Flash

While most imaging components on the CM1 would not look out of place on a high-end compact camera, the flash is unfortunately a simple LED, as can be found on many smartphones, and not a more powerful Xenon flash that is used on most dedicated cameras. Exposure is usually good but the flash's lack of power means that the camera increases ISO to very high levels, which results in a loss of image detail and an increase in noise.

In very dark conditions extremely slow shutter speeds lead to image shake as the flash is not sufficiently strong enough to freeze motion. But not only does the flash lack power, as you can see in the samples below, auto white balance has serious problems when the flash is mixed with ambient light. All in all, it's safe to say that using the CM1's flash is best avoided.

ISO 1000, F2.8, 1/30 sec
Lack of detail, yellow color cast
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ISO 1250, F2.8, 1/30 sec
Mixing flash and ambient light leads to a strong yellow cast.
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ISO 3200, F2.8, 1/8 sec
A high ISO value and slow shutter speed leads to a very soft image.
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