Sony Alpha NEX-7 vs Sony Alpha NEX-5N vs Canon EOS 60D Noise
The above shot was taken with the the Sony Alpha NEX-7 with the lens set to 20mm (30mm equivalent) and the aperture set to f5.6 in Aperture priority mode. At its base sensitivity setting of 100 ISO the NEX-7 metered an exposure of 0.6 seconds. The NEX-5N metered the exact same exposure, as did the Canon EOS 60D. Both the NEX models struggled to autofocus in the dimly lit church so I used manually focus with peaking activated to focus on the area from which the crops are taken. The EOS 60D managed to autofocus without a problem. The NEX-7 noise crops generally reflect what we saw in the outdoor test crops: the higher resoution 24.3 Megapixel sensor is, as you'd expect, more prone to noise than the 16.1 Megapixel sensor of the NEX-5N, but not as much as you might think. At the base 100 ISO setting there's a slight graininess to the detail, but it's neither intrusive, nor unpleasant. The interesting thing is what happens at the 200 and 400 ISO sensitivity settings. If the NEX-7's sensor was performing on the edge of its capabilities in terms of signal to noise ratio, you'd expect the Sony engineers to have a real job on their hands to keep noise under control as the signal is amplified and the sensitivity increases. If they did, you wouldn't know it from these crops, the 200 ISO crop is barely distinguishable from the 100 ISO one and even at 400 ISO, though the noise is a little more evident, this is an excellent result. In fact, right up to 800 ISO the NEX-7 does a first rate job of balancing effective noise reduction with retention of fine image detail. At 1600 ISO the noise is begining to get intrusive and the processing to minimise its effects is having a marked effect causing smearing of the fine to medium image detail. Even so, at 3200 ISO the result is still good enough to use at smaller sizes and even 6400 ISO is passable. At 12800 and 16000 ISO even at small sizes things look very bitty, but not many cameras wil let you shoot at full resolution at these high sensitivities, so it's good to have them. You'll get better results using the Handheld Twilight scene mode, which you can see on the next page. Compared with the NEX-5N the results from the NEX-7 hold up very well, particularly at the lower sensitivities. At 100, 200 and 400 ISO the NEX-7 is marginally noisier than the NEX-5N but you have to look very carefully at these 100 percent crops to spot it - that's a very impressive achievment. At 800 ISO the quality starts to diverge first by a little, then an increasing amount - the 1600 ISO crop from the NEX-7 is much granier than the one from the NEX-5N and by 6400 ISO there's a stop between them - the 5N 6400 ISO crop looks a lot like the 3200 ISO crop from the 7N. Another thing worth pointing out here is the level of detail in the lower sensitivity crops. Though the NEX-7 detail is larger, it's no better resolved than the smaller detail in the 5N crops. Compared with the crops from the 18 Megapixel Canon EOS 60D the NEX-7 again holds its own. At the lower ISO sensitivities detail in the EOS 60D crops is softer but there's little if any daylight between the two in terms of visible noise. In the middle to high ISO sensitivities though the NEX-7 gains the upper hand. At 400 ISO the 60D is marginally noisier and by 1600 ISO the difference is clear to see; it's still not a massive difference, but it is significant. Given that both cameras share same-sized APS-C sensors, and the NEX-7 has a third more photosites than the EOS 60D you'd expect these results to be the other way around, so all the more credit to Sony for the NEX-7's excellent low-light performance.
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