Sony NEX-5N External Electronic Viewfinder
Among the concessions made in the name of attaining the Sony NEX-5N's compact size was the elimination of any form of built-in viewfinder, with the LCD display serving as the sole method of framing and reviewing images. Sony does offer an external viewfinder accessory, however, catering to those who prefer the feel of framing with the camera held up to their eye.
There are two main camps for external viewfinders: optical or electronic types. With the earlier NEX-5 model, Sony offered only an optical type, which had not only the advantage of a true optical image, but also offered a savings in battery life, and removed the need for delicate electrical connections. On the downside, though, the separate optical path meant that the accessory was prone to parallax with nearby subjects, and there was no zoom capability. Instead, the field of view was a fixed 16mm, with a 15mm eyepoint.
That FDA-SV1 external optical viewfinder accessory is still compatible with the NEX-5N, however there's also a new FDA-EV1S electronic viewfinder accessory. Like the optical viewfinder, it's an optional extra, but the good news is that it is based around the same Organic LED panel that's used for the built-in electronic viewfinder in the Sony Alpha A77. While it's not perfect--we've previously noted issues with blocked-up shadows and overall brightness in our A77 review--it's still the best electronic viewfinder we've seen, with incredibly high resolution, smooth motion, and minimal lag.
You'll note that we said it's based around the same panel as the A77's viewfinder: Sony's spec sheets and our own experience suggest that the optics differ somewhat from that camera's built-in EVF. While magnification and coverage remain at 1.09x and 100% respectively, the eyepoint of 23mm from the rear lens surface / 21mm from the frame is rather less generous than the 27mm / 22mm of the A77's viewfinder. Sony doesn't provide a specification for refresh rate or brightness, but on the plus side, the 13mm-diagonal OLED panel has an extremely high resolution of 2,359,296 dots, and a useful -4.0 to +1.0m-1 dioptric adjustment range.
The FDA-EV1S also bests the A77's built-in EVF in one respect, since it can be tilted upwards 90 degrees when shooting low to the ground. A built-in proximity sensor is used to automatically enable the electronic viewfinder when brought to your eye. It's also possible to manually enable or disable the EVF with a "Finder/LCD" button on the left of the viewfinder itself.
The FDA-EV1S electronic viewfinder weighs 26 grams / 0.9 ounces without the eyepiece cup, and comes bundled with a plastic cap that protects its electrical connections when not in use, as well as a small carrying pouch to prevent accidental scratches.
Both the optical and electronic viewfinder accessories mate into the same proprietary Smart Accessory Terminal 2 that's used for other accessories including flash strobes, meaning that it's not possible to use either viewfinder type for flash photography. The FDA-SV1 optical viewfinder is priced at around US$200, and the the FDA-EV1S viewfinder is about US$350.
Sony NEX-5N Full-time Live View
By its nature, the Sony NEX-5N is always in "Live View" mode. In that respect, it's like any point & shoot digicam with a rear-panel LCD that works as its viewfinder. The differences with this camera are that it has interchangeable lenses, and has a larger sensor to provide better low-light performance than typical pocket cameras.
The Sony NEX-5N's optional electronic viewfinder offers output similar to that of the main LCD display, but with a significantly higher resolution, and a 4:3 aspect ratio. As you change exposure settings, the display changes to reflect what the captured image will look like, also known as "exposure simulation." Much like the NEX-5N's main LCD display, Sony has provided a brightness adjustment for the electronic viewfinder, which can be found in the Setup menu. By default, viewfinder brightness is controlled automatically.
Only two display modes are available through the electronic viewfinder accessory: basic info, and histogram. Both displays include the exposure mode, battery and flash card remaining, aspect ratio, quality and compression of still images, movie mode, SteadyShot mode, shutter speed, aperture, and ISO sensitivity, as well as an exposure level display. Through the Settings menu, you can also enable one of three styles of grid displays.
When the viewfinder is in use, it's possible to configure the main LCD not to provide a live view image at all, and instead to act solely as a roomy status LCD, showing camera setup info.
Viewfinder Test Results
Excellent accuracy from both the optional electronic viewfinder and LCD monitor.
The Sony Alpha NEX-5N's optional FDA-EV1S XGA OLED electronic viewfinder and LCD monitor both showed just slightly below 100% (~99.7%) coverage with our Sigma 70mm f/2.8 prime lens. This is excellent performance, though not a surprise given the electronic viewfinder and LCD are deriving their images from the main imaging sensor.