85mm lenses are believed by many to be the ultimate portrait lens. It's the right length to keep you a reasonable distance from your subject without producing too much distortion while producing ultra-sharp images with beautiful bokeh. In the video above and the post below, we will be comparing Sony's $1,800 85mm lens to Samyang's $700.
The Sony 85mm f/1.4 has more features than the average lens. Its aperture can be controlled digitally via camera dial (like most modern lenses) or it can be controlled mechanically by the aperture ring on the lens. The aperture ring can be set to click every 1/3 stop or it can turn smoothly (a feature some specialized videographers will appreciate). The lens also has an autofocus lock as well as an autofocus/manual switch. The Samyang version has none of these features and only has a focus-by-wire focus ring on it.
Although I can appreciate the extra features on the Sony version, I personally will never use any of them, so to me, they aren't of much value.
While shooting wide open at f/1.4, both lenses suffered from some vignetting (darkening of the edges), but Sony's lens was clearly better. The Samyang lens had slightly darker edges at f/1.4, but looked very similar to the Sony once you stopped down to f/2 and beyond.
Both images looked almost identical throughout their f-stop range in the center of the frame, but on the edges, the Sony was slightly sharper, especially wide open.
The Sony produced a cooler image than the Samyang, but after a slight white balance shift, the colors looked identical from both lenses.
When shooting directly into the sun, the Sony lens was able to capture a much more accurate, contrasty image with a small lens flare. The image taken with the Samyang lens had a larger flare that produced a more washed out image. In normal shooting environments, the image quality out of both lenses looked very similar, but if your subject is extremely backlit, the Sony will perform better.
I wouldn't have normally even done this test, but I read online that some people found that the Samyang had loud autofocusing. I found the opposite to be true. The Samyang sounded very similar to other lenses that I own, while the Sony had the strangest autofocusing noise I've ever heard in any lens. Not only was it strange, but the Sony's autofocus was significantly louder as well.
Although I felt like the Samyang lens might have been slightly faster, it was too close to tell for sure. Both lenses were able to autofocus extremely quickly and with 100% accuracy in bright daylight.
Continuous Autofocus Speed
Although it was hard for me to tell on location, it's pretty easy to see in the video above that Sony's lens did perform better in our extreme continuous AF test. If you happen to be shooting video of people walking towards your camera (for example, at a wedding), it could be worth buying the Sony for this extra performance alone, but if you are a wedding videographer, you probably aren't going to be shooting with an 85mm lens. For standard filming, the Samyang lens was able to hold focus on a shifting subject just as well as the Sony, but under extreme conditions, the Sony was better.
The Sony 85mm f/1.4 is a better lens in almost every way, but only by a small margin. If it cost a few hundred dollars more than the Samyang, the Sony would be an easy choice, but it doesn't. The Sony 85mm f/1.4 costs $1,100 more than the Samyang, and that price is hard to justify.
For the average photographer, I'd recommend buying the Samyang 85mm f/1.4. For 40% of the cost, you are getting 90% of the results. With the extra money, you could buy another camera body, lens, or light. But, of course, if you have the extra money to spend and you want the absolute best or you need specialized features like the smooth aperture ring, flare reduction, or continuous AF performance, the Sony version might be worth the hefty price.