Big claims were reported for the capabilities of the new OM System OM-1, and we now have Adobe Camera Raw support, allowing us to check those claims in our standard test scene. The company briefed that the OM-1 offered a 2EV improvement in noise performance and a 1EV improvement in dynamic range.
However, these claims did not appear in such striking terms in the press release about the camera, where the only reference to a two stop improvement in noise referred to the multi-shot high res mode (where re-sampling the scene and combing the results improves noise and, as a consequence, dynamic range).
Studio scene
Our test scene is designed to simulate a variety of textures, colors and detail types you'll encounter in the real world. It also has two illumination modes to see the effect of different lighting conditions.
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There's not a big difference in detail levels between the OM-1 and the E-M1 III at low ISOs, though the OM-1's JPEG engine appears to render fine detail a little better.
At higher ISOs$(document). ready(function() { $("#icl-5568--1138071457"). click(function() { ImageComparisonWidgetLink(5568); }); }) the newer camera appears to preserve detail rather better, and gives a rather larger-grained appearance to the noise in areas without detail$(document). ready(function() { $("#icl-5569-91814885"). click(function() { ImageComparisonWidgetLink(5569); }); }). Look at the Raw and there's no appreciably difference in noise between the OM-1 and E-M1 III$(document). ready(function() { $("#icl-5570-618070502"). click(function() { ImageComparisonWidgetLink(5570); }); }), which is in-line with what we've seen in previous BSI and Stacked CMOS sensors. It's worth noting, though, that the OM-1 keeps up with the older camera's highest ISOs$(document). ready(function() { $("#icl-5571--1476550032"). click(function() { ImageComparisonWidgetLink(5571); }); }), which is impressive, as this is where we'd expect its more complex design (with four photodiodes per output pixel) to start to count against it.
It's not a 2 stop improvement though$(document). ready(function() { $("#icl-5573-913441583"). click(function() { ImageComparisonWidgetLink(5573); }); }), even in in terms of JPEG performance$(document). ready(function() { $("#icl-5572--143058337"). click(function() { ImageComparisonWidgetLink(5572); }); }). However, there is the option to run the Raw files through the OM Workspace software, which uses AI-trained noise reduction to preserve detail while reducing noise.
Look at the multi-shot high-res images$(document). ready(function() { $("#icl-5574-463346707"). click(function() { ImageComparisonWidgetLink(5574); }); }), though, and you'll will see two-stop improvement in noise, if viewed at a common output size. High-res mode is only available up to ISO 1600.
Dynamic range
In terms of dynamic range, it's a similar story. If you brighten an ISO 200 image to the same level as an ISO 1600 shot, there's no appreciable difference in noise. This shows that there's very little electronic (read) noise being added by either sensor. Traditionally, high ISOs has lower read noise levels because amplification lifted the captured signal (and whatever read noise arrives upstream of the amplified) above the level of any other read noise. Here there's very little difference.
This gives Raw shooters the option of finding an exposure in low light, then lowering the ISO setting while maintaining the other settings, then brightening the result back up. This preserves highlights (such as a sunset backdrop or bright neon signs) that would otherwise be amplified to the point of clipping.
Our Exposure Latitude test shows that there's a similar amount of noise if you dig into the deepest shadows, as there would be on other recent Micro Four Thirds sensors. This is consistent with the performance of the majority of modern sensors, taking size into account.
In both instances, if your scene is static enough to allow the use of high resolution mode, you gain the DR benefit of combining multiple images, and performance rises accordingly.
ISO Invariance | Exposure Latitude
A performance that's essentially the same as preceding models, with any improvement being in terms of JPEG processing may seem a little anticlimactic, after the widespread discussion of improvements measured in whole stops. But, just as we were impressed by how little DR the Sony a1 had to give up, in return for its impressive readout speed, here we're seeing a sensor with quad-pixel X-type AF and twice the previous readout speed without any significant image quality cost. That's an impressive result, given what the speed should allow the camera to do.
. dpreview.com2022-3-8 18:00