Full-Frame E-mount. As part of the FE line of lenses, the FE 50mm f/1.4 is designed to cover a7-series cameras’ full-frame sensors. Since it’s an E-mount lens, it’s also fully compatible with APS-C NEX cameras.

Normal Angle. When used on a full-frame camera, the 50mm focal length offers a normal field of view that’s useful for just about any type of photography. With an APS-C sensor camera, you’ll have a portrait-range focal length of about 75mm. The fast f/1.4 aperture offers both great low-light performance and shallow depth-of-field control.

Direct-Drive Super Sonic Wave Autofocus System. This system uses piezoelectric elements oscillating at ultrasonic frequencies to provide fast, highly accurate, and nearly silent performance that’s great for still and video use.

Advanced Optics. The FE 50mm f/1.4 is based on the Zeiss Planar optical design. That means twelve elements in nine groups, including one Advanced Aspherical element, one aspherical element, and one extra-low dispersion element, all of which work to combat aberrations and distortions. Eleven circular blades keep the bokeh beautiful across the aperture range, while the T* coating means you get that Zeiss color and microcontrast.

High-Quality Build. The FE 50mm offers dust- and moisture-resistant sealing for use in less-than-ideal conditions. The all-metal barrel gives the lens a solid feel, and boasts a smooth, responsive manual focus ring. The manual aperture ring allows you to disengage click stops for smooth aperture adjustment when shooting video.

https://blog.lensprotogo.com/2017/03/27/the-best-lenses-for-photographing-children/