Sony a5100 Camera Trades Some Function for Smaller Form

Sony hasn't made decisions for camera buyers easier today (Aug. 18) as it introduces a new mirrorless, interchangeable-lens model, the 24-megapixel Alpha a5100. On sale in early September (in black or white) for $699 with 3X zoom lens or $549 without, the new a5100 is $100 less than its big sibling, the high-performance a6000, taking away some features while adding others. 

The most noticeable change is in size. The a6000, at 10 ounces (without lens), is hardly a giant; but the a5100's 7.9-ounce body, measuring 4.3 x 2.5 x 1.4 inches, is truly tiny — not much larger than some bigger point-and-shoot or bridge cameras. Yet it offers all the main components of the a6000, including the identical DSLR-sized sensor and Sony's new Bionz X image processor. (See photo and video samples below of what the a6000 can do.)

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Sony a6000 photo | Credit Sean Captain

Sony a6000 photo | Credit Sean Captain

These components were formidable in our tests of the a6000 (see review), which has superfast phase- and contrast-detection autofocus, even at night, as well as crisp images, with minimal graininess even at a stratospheric light sensitivity of ISO 12,800. (See photo below.) Sony told us that the a5100 should post the same results, except a slower shooting speed of 6 frames per second (with autofocus and autoexposure adjusted for each shot) vs. the a6000's 11fps. But 6fps is still solid. The $1,200 (body only) Canon EOS 70D —our favorite DSLR — shoots just one more, at 7fps.

Sony a6000 photo | Credit Sean Captain

Sony a6000 photo | Credit Sean Captain

What else don't you get for the lower price? The a5100 lacks the nice OLED electronic viewfinder (EVF), which could be a dealbreaker for photography purists and folks switching over from DSLRs. But for people used to smartphones and point-and-shoots, it may hardly matter. What they do get is a touchscreen (not available on the a6000) that tilts up 180 degrees for selfies — seemingly a requirement for all new cameras. The screen should also make it easier to navigate Sony's sometimes-confusing menus. 

Another negative for serious photographers: The a5100 lacks a "hot shoe" connector on top for attaching a larger flash or microphone. The build-in mics and popup flash will have to suffice.

Video: an unfortunate compromise

The a5100 is well equipped for video, able to shoot in the very high-quality (and data hungry) XAVC S2 and AVCHD formats up to full HD 1080p at 60fps. It also shoots in the compact and easy-to-share MP4 format, though at lower quality. A first for Sony, the a5100 can record video in both formats, so you can easily share the MP4 and have the higher-quality clips in case you want to produce something fancier. (See low-light sample below from the a6000.)

Except you won't have fancy audio. With neither a mic input jack nor a hot shoe, you're stuck with the built-in mics, so the sound quality won't equal the promised high video quality. That said, we got sufficient sound for a decent clip with the a6000's built-in mics, shooting in very low light at full-HD, and cinema-style 24fps. 

Who's the a5100 for?

If you consider yourself a serious photographer, look to the a6000 for its viewfinder, faster shooting, and expansion capabilities. Look also to its mirrorless rivals such as the $1000 Samsung NX30. Also check out comparable DSLRs like the $650 Nikon D3300 (see review)

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If things like OLED EVFs and hotshoes aren't things you think about, the a5100 should serve you well. We're saying that based on what we expect its components to deliver, namely fast autofocus and great low-light performance. It's hard to find a very close rival. The $600 Nikon 1 J4 (see review) is even smaller and also has very good autofocus, but mediocre quality in anything less than bright light. The $650 Samsung NX 300M has a similar design, including selfie screen, and also a combination of great autofocus and so-so low-light quality (though this model seems overdue for an upgrade). 

But the proof is in the shooting. We'll be back with a full review of the a5100 as soon as we can get our hands on one.

Follow senior editor Sean Captain @seancaptain on Flickr (sergiocapitano), and on Google+. Follow us @tomsguide, on Facebook and on Google+.

Sean Captain is a freelance technology and science writer, editor and photographer. At Tom's Guide, he has reviewed cameras, including most of Sony's Alpha A6000-series mirrorless cameras, as well as other photography-related content. He has also written for Fast Company, The New York Times, The Wall Street Journal, and Wired.