Olympus XZ-1 Review
Resolution Chart Comparison (JPEG)
Images on this page are of our standard resolution chart which provides for measurement of resolution up to 4000 LPH (Lines Per Picture Height). A value of 20 equates to 2000 lines per picture height. The chart is shot at a full range of apertures and the sharpest image selected. Exposure compensation set to deliver approximately 80% luminance in the white areas.
What we want to show here is how well the camera is able to resolve the detail in our standard test chart compared to the theoretical maximum resolution of the sensor, which for the charts we shoot is easy to work out - it's simply the number of vertical pixels (the chart shows the number of single lines per picture height, the theoretical limit is 1 line per pixel). Beyond this limit (when talking about line pairs usually referred to as the Nyquist frequency) the sensor cannot faithfully record image detail and aliasing occurs.
This limit is rarely attained, because the majority of sensors are fitted with anti-aliasing filters. Anti-aliasing filters are designed to reduce unpleasant moiré effects, but in doing so, they also reduce resolution (the relative strength and quality of these filters varies from camera to camera). In theory though, a sensor without an AA filter, when coupled with a 'perfect' lens, will deliver resolution equal to its Nyquist limit. Therefore, even though it may be effectively unattainable with normal equipment in normal shooting situations, an understanding of a sensor's theoretical limit provides a useful benchmark for best possible performance. Nyquist is indicated in these crops with a red line.
On this page we're looking at both JPEG and Raw resolution. For a (more) level playing field we convert the latter using Adobe Camera Raw. Because Adobe Camera Raw applies different levels of sharpening to different cameras (this confirmed) we use the following workflow for these conversions:
- Load RAW file into Adobe Camera RAW (Auto mode disabled)
- Set Sharpness to 0 (all other settings default)
- Open file to Photoshop
- Apply a Unsharp mask tuned to the camera, in this case 80%, Radius 0.7, Threshold 0
- Save as a TIFF (for cropping) and as a JPEG quality 11 for download
Raw files processed with a beta version of Adobe Camera Raw and may not represent final image quality. These will be updated when the finished software is available.
|JPEG (3648 x 2736) 4.1MB||RAW (3648 x 2736) 4.3MB|
The XZ-1's JPEG output doesn't contain quite the fine detail that can be seen in the converted Raw files. However, the JPEGs appear to have had a degree of noise reduction applied and some large-radius sharpening applied - meaning they don't have the same level of fine detail but the numbers have crisper edges.