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. For each camera we use the relevant prime lens (the same one we use for all the other tests in a particular review). The chart is shot at a full range of apertures and the sharpest image selected. Studio light, cameras set to aperture priority (optimum aperture selected), image parameters default. 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.

Note that while we usually compare both JPEG and Raw on the same page, here we've put just JPEG from both the RX1 and RX1R alongside one another, to compare the results with and without a low-pass filter. Look to the next page to compare Raw images from both cameras.

JPEG

RX1 (6000 x 4000) 4.6MB RX1R (6000 x 4000) 5.0MB

Vertical resolution - JPEG

RX1
RX1R

Horizontal resolution - JPEG

RX1 RX1R

In terms of actual resolution, there's not much difference between the RX1R and the RX1 in JPEG mode, although it is very clear that the RX1R's JPEGs are more prone to moiré than those from the RX1. The lines in our studio resolution chart begin to merge together a little beyond 2800LPH in images from both cameras, although the RX1R's output is a little sharper, giving the appearance of slightly greater detail up until around 3400LPH at which point moiré becomes intense.