The actual sensitivity of each indicated ISO is measured using the same shots as are used to measure ISO noise levels, we simply compare the exposure for each shot to the metered light level (using a calibrated Sekonic L-358), middle gray matched. We estimate the accuracy of these results to be +/- 1/6 EV (the margin of error given in the ISO specifications). In our tests we found that measured ISOs from the Ricoh were under-sensitive by around 1/3EV, meaning ISO 100 indicated = ISO 80 measured. It's not enough to make a significant difference in the real world, but is worth considering when you look at the results below.
Noise and Noise Reduction (JPEG)
The Ricoh produces similar amounts of noise to its rivals and does a reasonable job of balancing noise and detail retention, at least at moderate ISOs. Above ISO 3200 the detail is increasingly aggressively suppressed, with a loss of fine detail as a result. The camera's default settings (shown further down this page) actually pushes the noise reduction up (to Strong) at ISO 3200 - we'd be tempted to go the other way. Thankfully, with the GR, you have the option to keep the camera at a lower noise reduction setting until you feel it's absolutely necessary to increase it.
Noise Reduction options
The Ricoh allows a high level of control over its noise reduction. You can either choose 'Auto,' which applies a manufacturer-decided level of NR to each ISO. Or, you can select 'Manual,' and choose when the camera applied different levels of NR.
|The Auto mode applies different levels of noise reduction at pre-defined ISO settings.
However, there's also a manual mode that allows you to specify which ISO you want each level of noise reduction to kick-in at.
There are four levels of NR available from off to Strong. In 'Manual' mode, you can specify the thresholds at which noise reduction is increased. So you can keep NR low for longer than the default settings, but you can't apply less NR for high ISO settings than you chose for the moderate ISOs.
Below we've plotted the default 'Auto' settings (in purple) over the individual options, but it's fairly simple to apply the level of noise reduction you want for each ISO.
|The NR Auto setting applies increasingly high noise reduction as the ISO increases (It's using NR Strong by ISO 2500).|
ACR noise (ACR 7.4, noise reduction set to zero)
Here we look at the RAW files processed through Adobe Camera Raw (in this case version 7.4). Images are brightness matched and processed with all noise reduction options set to zero. Adobe does a degree of noise reduction even when the user-controlled NR is turned off.
The amount of NR applied 'under the hood' is not high, but it does vary by camera (Adobe is attempting to normalize output across different sensors), so inevitably we are still looking at a balance of noise and noise reduction, rather than pure noise levels. However, the use of the most popular third-party RAW converter is intended to give a photographically relevant result, rather than simply comparing sensor performance in an abstract manner.The Ricoh shows a very similar response to the Nikon - strongly suggesting the two camera's sensors are producing similar (indeed near-identical) output. Visible noise and detail levels are very consistent between the two cameras. DxOMark's assessment of the two sensors also draws very similar conclusions for both - with both technical and visual analysis supporting the idea that there's little to choose between the cameras in terms of Raw performance.