Monday, October 21, 2013

Sony A7r and A7 Focus Speeds

sony a7r zeiss 35mm sonnar

Sony A7r with Zeiss 35mm f/2.8 Sonnar


One of the major differences between the Sony Alpha 7r (A7r) and the Alpha 7 (A7) is their focusing systems. Both cameras have contrast-detection autofocus but the Sony A7 incorporates phase-detection autofocus for a hybrid system which adds speed and accuracy to locking focus. The videos show a slight difference in locking focus for both cameras. More information below.

Sony A7 Focus Speed with Zeiss 35mm f/2.8 Sonnar


Sony A7r Focus Speed with Zeiss 55mm f/1.8 Sonnar


Sony Alpha 7rSony Alpha 7
Focus system TypeContrast-detection AFFast Hybrid AF
(phase-detection AF/contrast-detection AF)
Focus point25 points35mm full-frame:
     117 points (phase-detection AF)
APS-C:
     99 points (phase-detection AF)
     25 points (contrast-detection AF)

Sony A7r vs A7 Focusing System Comparison


sony

Contrast Detect Autofocus of the Sony A7 and A7r


The Sony A7r's autofocus system as explained by Sony:
Fast Intelligent AF

Fast Intelligent AF provides extremely fast AF performance despite the employment of a full-frame sensor. In fact, it achieves top-level AF speed in the full-frame category through the support of various advances including new lightning-fast BIONZ X, high-speed full-frame image sensor output, and a newly developed Spatial Object Detection AF algorithm that conducts focusing analysis in real-time using spatial frequency information to optimally control the lens drive.

sony

Phases Detect Autofocus of the Sony A7


The Sony A7's autofocus system as explained by Sony:
Enhanced Fast Hybrid AF

Enhanced Fast Hybrid AF combines speedy phase-detection AF with highly accurate contrast-detection AF, which has been accelerated through a new Spatial Object Detection algorithm, to achieve among the fastest autofocusing performance of any full-frame camera. First, phase-detection AF with 117 densely placed phase-detection AF points* swiftly and efficiently moves the lens to bring the subject nearly into focus. Then contrast-detection AF (Fast Intelligent AF) with wide AF coverage fine-tunes the focusing in the blink of an eye. Performance is dramatically improved beyond that of previous Fast Hybrid AF systems through a number of major advances in high-speed contrast-detection AF, including faster communication with the lens made possible by the advanced Spatial Object Detection algorithm. Other advances include optimized image-sensor data read-out, swifter processing of AF-related data by the new BIONZ X image processing engine, and a more efficient lens drive that reduces back-and-forth lens movement.

* 99 points when an APS-C lens compatible with Fast Hybrid AF is mounted.

sony a7r zeiss 35mm sonnar

Sony A7r with Zeiss 55mm f/1.8 Sonnar