In this article, Keiko (of GearAddix) has helped put together a short video review of the new Rokinon 300mm F/6.3 Mirror Lens for micro-four thirds camera systems [Thanks Keiko]. If you're looking for that long zoom on a budget, this new mirror lens from Rokinon is a great option, and yes it will work on a BlackMagic Pocket Cinema camera as well.

Unlike traditional glass element lenses, the incoming light is reflected by a main mirror on the back towards a secondary mirror (located in the front), and back again towards the camera's sensor. By folding the light, these lenses can offer incredible distance while staying very compact and especially very lightweight.

Unfortunately this design also has a few disadvantages such as aperture control. This Rokinon 300mm mirror lens has a fixed F/6.3. This is the reason why an ND filter was required on an especially bright day. I guess that's not too much of a problem, as many DSLR shooters tend to carry ND filters nowadays.

B+W Static ND Filter
Tip: At this distance static ND filters are best to retain sharpness

Also, sharpness and contrast are typically just mediocre with mirror lenses, but i'm very surprised at how much this new Rokinon 300mm mirror lens retains. They've done a great job creating a very compact MFT lens that still retains sharpness, detail, color, and contrast.

Another prominent tell-tale sign of a Mirror Lens is an odd donut-like effect (white rings) that show up on out-of-focus highlights. While lenses with an aperture blade are capable of producing perfectly round highlights, Mirror lenses will create a round donut-like out of focus highlight as seen in the image below.

For a stylized effect there are groups who find this aesthetically interesting, when used with portraits (see example photos here).

Due to it's fixed aperture of F/6.3 optimal conditions are preferred (lots of light), and keep in mind these lenses do not offer image stabilization. Still, maybe not so much of a problem as many of today's M43 cameras are starting to add Image Stabilization at the sensor level.

Mirror lenses have been around for years, and are available in focal lengths past 1600mm. The most expensive of which still falls under just $300 bucks. That's a pretty amazing price for the distance you get, but obviously you have to consider if those mirror-lens 'differences' work for you. Find a few options below.

Variety of Rokinon Mirror Lenses - via eBay

So now that you've checked out this video review, and some of the other mirror lens image samples (found here), what do you guys think about Rokinon's latest 300mm F/6.3 Mirror Lens for Micro Four Thirds? Leave your comments below.