Although its the same size as the Sony NEX-5T that it replaces, the new Alpha 5100 has the same 24.4-million-pixel CMOS sensor and Bionz X processor as the Alpha 6000 above it in the Sony compact system camera line-up.
Another key change is the increase in the number of autofocus points to 179 for phase detection and 25 for contrast detection. The NEX-5T also had a hybrid AF system, but it only had 99 phase detection points in addition to the 25 contrast detection areas. This gives the new camera far greater coverage and only the outer edges of the imaging frame are not covered.
In addition to single AF and continuous AF, the A5100 has an Auto AF mode in which it decides whether to use single or continuous AF depending upon whether it detects the subject to be moving.
This hybrid AF system also operates in Movie mode and footage maybe saved in AVCHD, XAVC S or MP4 format, or in XAVC S and MP4. Simultaneously. This gives the easy sharing capability of MP4 with the high data content of XAVX S.
In addition to Focus Peaking to indicate areas of highest contrast (focus), there is a Zebra display to show areas approaching burning out and markers with grid lines and the centre point can be shown on screen to make framing easier.
Like the NEX-5T, the A5100 has a 3-inch 921,000-dot LCD screen that is touch-sensitive and can be flipped up through 180 degrees for taking selfies. Touch-control is again fairly limited, however, as it can only be used for setting the AF point or tripping the shutter.
Thanks to the new processing engine, sensitivity range also stays the same at ISO 100-25,600, despite the increase in pixel count.
While the NEX-5T had a hot-shoe with an accessory connection but no pop-up flash, the A5100 has a pop-up flash (Guide Number 4m @ISO 100) but no hot-shoe.
Like the NEX-5T, the Alpha 5100 has Wi-Fi and NFC connectivity and is compatible with PlayMemories apps to expand its featureset. With the appropriate app in place, images can be directly uploaded to Facebook and the like.
Build and handling
At 109.6x62.8x35.7mm the Alpha 5100 is smaller than the A6000 (120x66.9x45.1mm) and slightly smaller than the NEX-5T (110.8x58.8x38.9mm) and this has meant the loss of the control dial on the top of the camera. As a result the Alpha 5100 makes greater use of the navigation controls and it's a shame that the menu (which is the same as the A6000's) can't be navigated via the touch-screen.
However, the buttons on the back of the camera can be customised to reach your most commonly used features.
Despite its small size and light weight (224g) the A5100 feels solidly made and has a decent grip with a textured coating so it's comfortable and secure in your hand.
The screen is also bright and clear, and responds quickly to touch.
I've only used a pre-production sample of the Alpha 5100 so far and I wasn't allowed to take any pictures for publishing here. However, as it has the same sensor and processing engine as the A6000 we can be pretty confident that the A5100 will produce high quality images. We were very impressed with the Alpha 6000 when we tested it.
We found that renders detail very well although smoothing is visible in some areas at 100% from around ISO 400. Noise, or its control only becomes problematic at normal viewing and printing sizes at around ISO 6400. In our review of the A6000 we suggested using a maximum of ISO 3200 if you want to make A4 prints, bit up to ISO 12800 is fine for or sharing images online at small sizes.
We also found that the metering and automatic white balance systems general do a good job, but in high contrast situations you may need to apply some exposure compensation. On the whole, the A6000 produces pleasantly saturated colours and I anticipate the A5100 doing the same.
My first impressions of the Sony Alpha 5100 are very good, but I want to use a full production sample in anger before I pass judgement on its handling now that the control dial that was on the top of the NEX-5T has gone. However, it seems straightforward and easy to get to grips with the camera.
Sony appears to have produce a pleasant little camera that should be capable of producing image that are as good as those from the Alpha 6000.
The Sony A5100 price will be around £550 (US$700, AU$899), including kit lens, and is available to pre-order now.