Editors' note: Several of the design, features, and shooting options are identical between the Nikon Coolpix P520 and the Coolpix P510 we reviewed earlier, so readers of the earlier review may experience some deja vu when reading the same sections below.
For the Coolpix P520, Nikon's flagship megazoom, very little has changed from its predecessor, the P510. Nikon put in a new 18-megapixel backside-illuminated (BSI) CMOS sensor, but it has the same 42x, f3.0-5.9, 24-1,000mm lens. The bulk of its other features remain unchanged, too.
That's not a bad thing since that's still one of the longest zoom lenses available, and the P510 had a nice helping of shooting options to keep even experienced shooters happy.
However, the P520 is still lacking things like a hot shoe, mic input, fast direct control over main settings, and raw support. Also, Nikon didn't make any improvements to autofocus speeds -- something the P510 needed and something Canon, Sony, Fujifilm, and Panasonic have been improving on with their competing models. The P520's photo quality is also about the same as the P510's, but in this case, that's a good thing.
In addition to the 2-megapixel resolution bump, the P520 gets a new flip-out, rotating 3.2-inch LCD; a lower starting sensitivity of ISO 80; two more shots in its full-resolution burst mode, so now it can capture seven in a row; and support for Nikon's tiny WU-1a Wi-Fi adapter, so you can wirelessly connect to iOS or Android devices for viewing or sharing your photos and videos.
For P510 owners, there's not a lot of reason to upgrade (and even if you don't already have a P510, you might consider hunting one down instead of the P520 if you can get it at a good price). But for first-time buyers, the P520 is a strong megazoom for those who don't care so much about having extra features they may never use.
In terms of photo quality, the Nikon Coolpix P520 is very good to excellent, and perhaps just a touch better than the P510 it replaces. The extra megapixels really don't help much except with well-lit macro shots or frame-filling portraits; looking at the photos at 100 percent only reveals noise and artifacts. Basically, don't be fooled by appearances -- the P520 is not as good as a digital SLR. For its price and features, though, most people should be more than happy with its results.
At ISO 80 and ISO 100, subjects look sharp with fine detail good enough for large prints up to 11.5x15. Things look slightly softer as you go up in sensitivity and noise reduction increases, but it isn't until you reach ISO 800 that subjects lose significant detail and look a little smeary at smaller sizes onscreen or in prints. If you leave ISO in Auto, the camera tends to go with higher ISO settings when the lens is zoomed in even when you have plenty of light. If you're not trying to freeze motion, it's best to take back some of the control from the P520 and manually select your ISO.
ISO 1600 is OK for Web use, especially if the subject doesn't have much detail to begin with; things just get a little too soft and smeary and colors look slightly duller. The highest sensitivities really aren't usable for much, though if you're used to bad low-light smartphone photos, they'll be better than those. (Read more about photo quality and the camera's capabilities in the sample picture slideshow above.)
Video quality is very good, certainly good enough for Web use and nondiscriminating TV viewing, and the stereo mics work well. The zoom lens does function while recording, but you will hear the motor in quieter clips as you use it. However, a bigger issue is the camera's slow autofocus when zoomed in; you may need to zoom back out a little to get a solid lock on your subject.
Though the photo quality isn't very different from the P510's, the P520's shooting performance seems to have slowed some. Where the P510 took barely more than a second from off to first capture, I found the P520 averaged about 2.3 seconds. Shot-to-shot time both with and without flash was about 2.3 seconds, too, which is longer than the 1.7-second time of the P510.
The camera's high-speed burst will capture at 7 frames per second at full resolution for up to seven frames (though I clocked it at 7.6fps). Unfortunately, after you fire off those seven shots, you're left waiting about 2.5 seconds for each frame to save before you can shoot again. Other continuous-shooting options include a low-speed full-resolution burst capable of 1fps for up to 30 frames and 120fps and 60fps bursts that capture up to 60 shots at VGA and 1-megapixel resolution, respectively.
Shutter lag -- the time it takes from pressing the shutter release to capture without prefocusing -- is 0.5 second in good lighting, which is tolerable, but in our low-light test with less scene contrast, the shutter lag averaged 1.9 seconds. Once you start extending the lens, the camera takes even longer to focus. Once you get out to the 1,000mm position, it can be very slow to focus. This isn't unusual, just something to be aware of if you're going to shoot fast-moving subjects at the telephoto end of the lens. On the other hand, Sony, Panasonic, Canon, and Fujifilm have all improved autofocus speeds in telephoto, making this Nikon one of the slower high-end megazooms available.