Noise, resolution and sensitivity
Image: In these unedited JPEG and raw images, detail is much crisper in the raw file. However, the JPEG does a good job with the colours, resulting in bold, realistic blues
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured at the mid end of the zoom (approx 50mm). We show the section of the resolution chart where the camera starts to fail to reproduce the lines separately. The higher the number visible in these images, the better the camera’s detail resolution is at the specified sensitivity setting.
With the same 10.1-million-pixel resolution as its predecessor, it is impressive that the performance of the Lumix DMC-LX7 has been enhanced. Our resolution charts indicate increased centre sharpness, and the camera reaches the 24 mark in raw and the 22 mark in JPEG capture, when set to ISO 100 and an optimum aperture. More detail can be obtained from raw files. In JPEG images, there is a noticeable drop in sharpness at ISO 400, where luminance noise becomes apparent and noise reduction kicks in.
In the two years of the LX5’s lifetime, the expert compact camera market has moved on in terms of ability to resolve detail. For example, Sony’s Cyber-shot DSC-RX100 has an imaging sensor that is twice the size of the LX7’s (116mm2 compared to 49mm2) and twice the number of pixels, so it can resolve a significantly higher level of detail and produce prints at twice the size.
I found the LX7’s ability to resolve detail and control noise is affected dramatically by the chosen aperture and ISO settings. For the crispest detail f/2.8-4 is best, with the new Leica lens capable of good results.
Likewise, to avoid mushy detail that results from luminance and chroma noise, using a setting under ISO 800 is advisable. In the highest native setting of ISO 6400 (which is a 1-stop advantage compared to the LX5), detail is not great, and there is banding and bruising over shadow and midtone areas in the scene.
