Lumix LX100 vs Sony RX100 III vs Sony A5100 Noise

To compare noise levels under real-life conditions, I shot this scene with the Lumix LX100, Sony RX100 Mark III, and the Sony Alpha A5100 (fitted with the 16-50mm kit zoom), within a few moments of each other using their best quality JPEG settings, and at each of their ISO sensitivity settings. I matched the field of view on each camera and set them at an aperture previously determined to deliver the sharpest results.I tested all three cameras at each of their apertures and found f4 to be the sweet-spot for the RX100 III and LX100, while f5.6 was best for the A5100’s kit zoom. All three were set to their optimal apertures and compensation applied where necessary to match their exposures – what you’re looking at below are entirely comparable results.On this page I’m comparing their noise levels on JPEGs processed with the in-camera defaults, with the exception of disabling any contrast enhancement as this can increase artefacts at high ISOs. The crops as always are taken from the area marked by the red rectangle in the thumbnail above left and presented here at 100%. The Lumix LX100, Sony RX100 III and Sony A5100 show progressively tighter crops because of their steadily increasing resolution. Note I hadn’t expanded the sensitivity on the LX100 when I made this comparison, so my LX100 results start at the base sensitivity of 200 ISO.At their lowest ISOs you’ll notice the RX100 III delivers the crispest details, thanks to its combination of high resolution, sharp lens and crisp image processing. The Lumix LX100 is also sharp, but its resolution means at the lower sensitivities it’s simply out-resolved by the RX100 III. Meanwhile the softer kit zoom of the A5100 coupled with slightly less punchy processing means it looks a little soft in comparison. The interesting thing is whether the LX100 will match the real-life detail of the RX100 III at higher sensitivities thanks to its lower resolution sensor, and what advantage will the A5100 enjoy lower down with the biggest sensor of all.I’d say the Sony RX100 III enjoys the edge in real-life detail up to 3200 ISO, at which point noise brings it down to roughly the same resolving power as the LX100. At this point you’ll notice the A5100 enjoys a cleaner result with slightly higher detail.

At 6400 and 12800 ISO, the RX100 III looks the noisiest, but it still records roughly the same degree of detail as the LX100. Meanwhile the A5100, while suffering, remains the cleanest of the three. The RX100 III bows out at this point, leaving the LX100 and A5100 to struggle with a 25600 ISO maximum which doesn’t look pretty on either camera.

I think many people were hoping the LX100 would deliver decisively lower noise levels than the RX100 III thanks to its larger sensor and lower resolution, but in my crops below there’s not as much difference as you’d think. Yes at 3200 ISO and above, the LX100 looks less noisy than the RX100 III, but up to this point the Sony is resolving a little more real-life detail in my tests.

Of course what we’re also looking at here is the effect of each camera’s in-camera processing, so in my next test I’ll process the RAW files from each with exactly the same settings to see what degree of information they’re all starting with. In the meantime I’d say the A5100 is definitely the leader at the highest sensitivities as you’d expect given its much larger sensor, but the difference between the LX100 and RX100 III is smaller than you’d expect, and for much of the lower ISO range the Sony delivers more detail.

What this table doesn’t take into account though is the relative sensitivity each camera would use under the same conditions. The Sony A5100 may have the biggest sensor and unsurprisingly the lowest noise for identical ISO values, but if you’re using its kit lens, you’ll be forced to use smaller apertures than the LX100 and RX100 III, and higher ISOs to compensate. For example at their 24mm equivalent focal lengths, the RX100 III and LX100 offer a maximum aperture of f1.8 and f1.7 respectively compared to f3.5 for the Sony 16-50mm kit zoom. This is a two stop exposure difference, meaning when the RX100 III and LX100 are using, say, 400 ISO, the A5100 with its kit zoom would need 1600 ISO. At the long-end of their ranges, the RX100 III and LX100 offer apertures of f2.8 compared to f5.6 on the Sony 16-50mm zoom, again representing a two stop difference, and again requiring a sensitivity two times higher for the A5100. So if you’re using the A5100 with the kit zoom, you’ll need to take this into account when comparing sensitivities, and to my eyes the slower lens effectively eliminates any advantage of the bigger sensor behind it. If you want to exploit the potentially lower noise of the A5100’s bigger sensor over the compacts, you’ll need to put a brighter lens in front of it.

I’ll add my RAW comparisons soon. In the meantime head over to my Sony A5100 sample images or final verdict.