Thursday, November 15, 2012

DPP Solutions: Phase-Detect Adapter System

By Staff Published in More Gear
The Sony LA-EA2 mounted on a Sony NEX-5N.
The Sony LA-EA2 mounted on a Sony NEX-5N.
Professional photographers can't afford to wait for the camera to be ready to get a photo. This is especially true for photojournalists and street shooters who rely on instantaneous response. For many years, compact point-and-shoot-style cameras have had sufficient resolution and image quality, but their slow contrast-detect AF systems simply weren't up to the needs of a pro photographer.

Contrast-detect AF has steadily improved, and today there are a number of small cameras that let pros have the best of both worlds—speed and small size. But as good as they are, tricky situations where you're faced with low light levels or a scene with challenging contrast will be challenging for most contrast AF systems.

If you're shooting with a Sony NEX mirrorless camera, you have an interesting option in the LA-EA2 adapter. This device fits on the NEX body and allows you to connect Sony A-mount lenses like the highly-regarded Carl Zeiss A-mount models. That's only part of the benefit, though. As lens adapters go, the AL-EA2 is fairly large because it not only serves as a connection adapter, it also has a built-in phase-detect translucent-mirror AF system.

The Bulking Up Of Small Cameras

There seems to be a slow, steady bulking up of professional DSLRs to the point where the top-of-the-line models, while very robust, are also big and very heavy. In response, a lot of pros are embracing the more powerful and sophisticated mirrorless system for some of their shooting. These cameras are much smaller, but when it comes to travel, you'll find that you might still be fighting bulk due to the various essential items that have to come along. Cords and chargers are an area where most camera makers could stand to make some improvements. We hope to see manufacturers put some effort into this aspect of their smaller systems.
Using the LA-EA2, your E-mount NEX camera has full-time continuous phase-detect AF via a 15-point AF system with three cross sensors. Because of its translucent mirror technology, the full-time phase-detect AF applies to still shooting as well as HD video. The LA-EA2 has an aperture drive that enables auto exposure with all A-mount lenses (except teleconverters).

At the time of this writing, the Sony LA-EA2 is the only device of its kind that we're aware of. In this issue of DPP, we're featuring an article on modern-day street cameras—designated for their small size, high performance and image quality—and we expect to see this list of cameras expand as mirrorless technology in particular improves. Sony might not have the only adapter of this kind for long.

The LA-EA2 works just like the translucent mirror Sony "DSLRs." These are actually Translucent Mount Technology cameras where the mirror doesn't flip out of the way as the exposure is being made. Instead, the mirror reflects a small amount of the light to the AF system while the rest passes through the mirror to form the image on the image sensor. The LA-EA2 adapter has that phase-detect AF system built into it.

The LA-EA2 isn't for everyone. The downside is that the somewhat large adapter and the bigger A-mount lenses negate some of the space and weight savings of having an NEX mirrorless camera. However, we imagine a photographer with Sony DSLRs like the high-end A99 or A77 and a quiver of A-mount lenses who wants to add a compact camera like the NEX 7 to their bag will find the LA-EA2 to be ideal.
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