Rokinon 7.5 f3.5

The Rokinon 7.5 f3.5 fisheye lens is produced by the Korean lens maker Samyang. It is, as far as I know, the only lens Samyang makes exclusively for the micro-four-thirds platform. It’s their smallest lens. Most of Samyang’s lenses are very large and fast full-frame primes. Some of those lenses are offered for micro-four-thirds, but they’re still full frame (or in some cases APS-C lenses). The Samyang 10mm f2.8 is an APS-C lens weighing over a pound. Samyang offers a version for micro-four-thirds. The micro-four-thirds version weighs more than the version for APS-C DSLRs.

Fortunately, because the 7.5mm is f3.5 and designed exclusively for micro-four-thirds, it’s tiny, weighing less than 200 grams. It also uses less glass than most Samyang lenses: nine elements in seven groups. Less glass mean less flare, which leads to better contrast and richer color rendering.

How does the lens perform in terms of resolution? Let’s look at some sample images. Here’s an image shot at f5.6:

Let’s look at a center crop:

And an edge crop:

From these examples, it is clear that the center is quite sharp, The edge is sharp as well, although the far edge looks a little less sharp.

Here’s another example, also shot at f5.6:

Center crop:

Edge crop:

Again we see reduced resolution toward the far edges, but nothing drastic.

Let’s look at one more image shot at f5.6:

Center crop:

Corner crop:

There’s a bit of reduced resolution here in the far corner, but really pretty darn good for a far corner. However, this is the near corner (near, that is, to the camera), so we could be getting a bit of field curvature with this lens, which will enable better performance at near corners than at far edges or the far corner. We should keep in mind that with fisheye lenses the distortion is so extreme that edges and corners will often be of little importance. The following image illustrates the distortion of this lens:

Now one last image to take a look at performance close-up, at f3.5. I’m not a fast aperture shooter, so this is the only image I have illustrating the lens wide-open:

And here’s the crop of the center:

I won’t bother with the corners, as they are obviously out of the plane of focus. As can be seen, the lens is not as sharp wide-open. For best performance, stop down to f5.6.

Like most wide angle lenses under $1,000, this fisheye does have a bit of fringing, which, however, cleans up easily in Lightroom. There is, alas, a more serious type of fringing dealing with how the lens handles dark edges against a blue sky. Consider the following image:

Now this a screen capture of a 300% crop. We’re looking in quite close. But there is a slight light-bluish fringe. This is due to inferior rendering of objects against their background, when certain color values and contrast are involved. This defect will occasionally show up in cheaper lenses. You’re probably not going to find this in the expensive Panasonic and Olympus fisheyes. It is, to be sure, fairly minor, and unless you’re making large prints (or extreme crops), nobody’s going to notice it. But it’s there, in case you’re wondering.

The Rokinon/Samyang 7.5 f3.5 fisheye lens is a very fine budget optic. It’s sharp and contrasty. It’s small and light. It’s a fun lens to shoot with and, at around $250 new, doesn’t break the bank. Definitely a nice lens to add to one’s micro-four-thirds kit.

Some samples from the lens, all shot with the Olympus OM-D EM-5:

And here’s some infrared shots, from the EPL-1: