Monday, September 21, 2015

Sony RX100M3 vs Sony A6000

Left: Sony A6000       Right: Sony RX100M3

The Sony RX100M3 and A6000 are two of the best received cameras for first time shoppers and young families looking for something to take quality photos with...

If you think that these are supposed to be cutting-edge enthusiast-oriented cameras, you would be right. Neither are inexpensive, but since the very beginning they have been universally well regarded. The funny thing about well-reviewed serious-level products is that the good word filters down to the general consumer level as well. Even if they are loaded with specs that appeal to hardcore enthusiasts, both product lines have successfully crossed over from high-end enthusiast to mass-market consumer. This is is no small feat; there are many good cameras, but few at the higher end compel casual shooters.

Taking a step back, the camera industry has gone through a sea-change these past few years. It used to be that if you wanted quality you bought a DSLR, and if you wanted portability you bought a compact. Mirrorless and high end compacts have changed that and made for more choice in between. Whereas before casual shoppers spend somewhere between $500 to $700 USD for an entry-level DSLR, they are now more likely to spend the same amount on a mirrorless camera or a RX100M3. It's a rational choice; for almost the same quality as a DSLR from 3-4 years previous, you get a smaller and more compact system.

The Dilemma:

Which to choose? The RX100M3 is physically smaller and has better lens specs, albeit with a smaller sensor and no fancy motion-tracking phase-det4ection autofocus. The A6000 is one of the smallest of the APS-C mirrorless cameras on the market, but would be considered large to a user accustomed to point-and-shoots. It's only serious weakness is the SEL1650 kit lens that it is paired with, which is one of the most electronic-0correction reliant lenses on the camera market. In fact, the A6000 menu blanks out the option to turn-off in-camera lens corrections when this lens is mounted.

Both are good, both are small. One is smaller, one is more capable. If you wanted one camera, which to chose and which trade-off is better?

Comparative Effective Aperture

Here is the numerical difference between the RX100 III and the A6000 with kit lens in terms of equivalent aperture when compared to an APS-C sensor.  For fun, the Micro Four Thirds Panasonic GM5 and the almost-APS-C Canon G1 X Mark II are included. What does "effective" aperture mean? It's easiest to think of it as either measure of the amount of background blur that the camera/lens combination can develop under equivalent conditions, or as a comparison of the safe hand-held shutter speeds.

Camera Diagonal Crop Factor Effective Max Wide Aperture Effective Max Long Aperture

Sony RX100M3 0.56 3.2 5.0
Panasonic GM5 0.77 4.6 7.3
Canon G1X Mark II 0.83 2.4 4.7
Sony A6000 1.00 3.5 5.6

The winner here is the Canon G1X Mark II by virtue of having the brightest lens paired with the second largest sensor. What is surprising is that the RX100 III is actually a tad bit brighter than the Sony A6000 equipped with the kit lens, but not by enough to make a meaningful difference. There is something that must be noted, however, and that is that depictions of equivalent apertures between difference cameras assumes that the sensor efficiency is the same between each camera, which is rarely true.

The following is a visual depiction of what the difference looks like between the two cameras. The first set is a 100% crop at the point of focus, followed by a crop from the middle left of the frame at a display rack ~10 feet behind the focus target. In other words, the first crop gives you a general sense of what center sharpness and acuity look like, where as the second illustrates the quality of the bokeh.

24mm at the point of focus
24mm background bokeh

A few things to note: Both cameras are set to the same focal length, but the A6000 image is slightly larger because the pixel count is slightly higher (24mp vs 20mp). Also, the native aspect ration is different; the RX100M3 is 4:3 and the A6000 is 3:2. The latter doesn't affect the comparability for this instance, but it does alter how you might frame a scene between the  two cameras. As you can see, the amount of bokeh is roughly the same, if not slightly greater in the RX100M3. (Again, refer to the effective aperture table above). This is no mean feat for a small compact camera; it was unthinkable in years past that a compact could product the same amount of bokeh as an APS-C camera. Slap on a SEL 35mm f/1.8 OSS on the A6000 and it's a different story, of course. Another surprising thing is that even at the center, the RX100M3 lens produces more contrast and acuity than the A6000 kit lens.

Another set, with the lens set at maximum zoom this time:

70/75mm at the point of focus
70/75mmbackground bokeh

Same thing with regards to sharpness; the RX100M3 has a bit more bit and contrast, but at the long end of their respective lenses, the A6000 has the softer bokeh. The practical implication is that the RX100M3 easily keeps pace with the A6000 in kit form during good light... that is, when you can keep the ISO level low and if the dynamic range isn't an issue. This will also be true of the RX100M4, which uses the same lens and with which the image quality for stills photography doesn't differ significantly from the RX100M3. So what happens if you have to raise the ISO level?

Image Noise

The following is an ad hoc demonstration of the camera's JPEG output quality through the ISO range. Pay attention to the legibility of the soda bottles for detail retention (or lack thereof) as the ISO value rises, speckling in the broad colour patches for overall image noise, as well as the harshness of the reflections and shadows as dynamic range decreases. These samples are not directly comparable to similar samples found elsewhere in this blog because of variable ambient lighting conditions. Naturally, there is more processing leeway in the original RAW files, but comparing RAW files from different cameras can give one a false sense of fairness. Because each RAW format is different, the best and most representative results depend on each file being processed for best results. Often, different RAW files are compared at default converter settings, which is a bit like comparing default JPEG settings. Hence, for quick comparative purposes we are using the JPEG files out of the camera, as they can give insight into how the competing imaging engineers view the output of their respective cameras. Click on images for 100% crop view.

ISO 400
ISO 800
ISO 1600
ISO 3200

The difference in sensor area between 1/1" sensors and APS-C sensors is over 3x; roughly speaking, you would expect a 1.5-2 stop advantage for the APS-C sensor for the same number of pixels. That's roughly what you see here; ISO 400 on the RX100M3 is roughly comparable to ISO 1600 on the A6000. The practical limit before image noise becomes a serious consideration is ISO 800 on the RX100M3 and ISO 1600 on the A6000. That's just image noise; the A6000 also gets the nod for having better dynamic range as well.
However, if we factor back in the difference in lenses, the difference narrows. As we saw above, the RX100M3 produces sharper looking images than the A6000 with the lens set to maximum aperture. Recall that the RX100M3 lens is opens from f/1.8-2.8 through it's range (though it's mostly f/2.8, with f/1.8 only at the widest position) and the A6000 lens is f/3.5 to f/5.6. This means that you can shoot with the RX100M3 roughly 2 stops faster than the A6000 with the kit lens... which balances out the advantage of the larger sensor.

In other words, under most casual shooting situations where the light isn't a limiting factor, both cameras will produce excellent images, but that's once again largely due to the fact that the A6000 kit lens is the limiting factor. We're talking about rough equivalencies here, though. Even if the brighter lens balances out the larger sensor, the A6000 will produce crisper images given half a chance.

Concluding Thoughts

If you break down  the image quality in this way, the choice between the two cameras doesn't necessarily become easier. On a pure price/performance basis, the A6000 definitively wins; with the RX100M3, you do pay extra to have the camera squeezed into such a small package. If you are looking for a capable snap-shot device, both are excellent, but the hard choice comes down to where you fall on the size/performance continuum.

With thanks to Broadway Camera


  1. I had the similar dilemma and ended up choosing the A6000 - no regret so far. I was actually also considering the LX100 from Panasonic, as I already have the predecessor LX3.

    However, going with the A6000 definitely comes with more potential costs. I ended up purchasing the 50mm f1.8 oss and 55-210mm lenses.

    Nonetheless, I think the great opportunity cost is actually the time and effort that I have been (and will be) spending to learn and improve my photography skills. Can't really put a value to that.

    1. Bigger sensor/lens systems have more potential; under casual shooting all cameras do fairly well, but the higher up the food chain you go, the more there is to tap into as you progress in skill and knowledge.

  2. i had similiar dilemma. I use the camera for videography, my old camera (sony rx100 m2) have greats stabilizer. i saw many review that sony alpha 6000 dont have image stabilizer so it will shake when walking with it. i dont have choice, maybe next month will be bought one of them

    1. The A6000 kit lens is stabilized, but image quality is not that great. I find that the real problem with the A6000 is that it doesn't have a standard microphone input, you have to use the Sony XYST1M Stereo Mic if you want decent quality audio with your video. You'd have to go to the A6300 to get a proper standard mic input.