With the recent introduction of the new Samyang AF 50mm F1.4 FE Mark II, number of available AF 50mm F1.4 lenses for Sony's FE mount cameras increased to three. Sony Planar T FE 50mm F1.4 ZA was the best 50mm F1.4 lens for the mount so far but the problem with this lens is it is huge, heavy and expensive! Samyang AF 50mm f1.4 FE mark I was a good alternative but being company's one of the first AF lenses, it couldn't really compete with the Sony lens. Now with the new 50mm F1.4 FE Mark II, and the claimed improvements line better AF and optical quality, we believe Samyang will close the gap even further with Zeiss and become a great alternative.
Below you can see the size comparison of these three lenses. Samyang Mark II is the most compact and also the lightest of the three lenses. It is also smaller and lighter overall compared to Mark I that it is replacing although it has a larger filter thread at 72mm and diameter at 80mm compared to Mark I's 67mm filter thread and 74mm diameter.
Below you can find the main feature and specs comparison of these 3 lenses: