The Olympus MC-20 Teleconverter Is One of the Best 2x Models Available, But You Must Understand Its Limitations
A teleconverter is always a compromise. It's a way to transform a lens into something more than it was designed to be. This 2x teleconverter transforms an Olympus 40x150mm lens into an 80x300mm lens. It does the same for the Olympus 300mm lens, making it a 600mm lens. Or the 100-400mm lens into a 200-800mm lens! But the compromise occurs because these lenses were not designed for those focal lengths and adding more lens elements to the path of the light while at the same time moving the lens farther away from the image sensor reduces the aperture (which reduces the amount of light entering the camera) and reduces the portion of the original optical image circle that exposes the image sensor (thereby reducing the optical resolution).
I've used some 2x teleconverters (like a Tamron model that came with a 500mm catadioptric lens, converting it into a 1000mm lens) that are horrible. The Tamron teleconverter softens the image so much and flattens the contrast so you're almost better off just using the lens without the teleconverter and enlarging the image digitally in Adobe Photoshop or Topaz Lab's Gigapixel AI.
But Olympus stands apart. The quality of its teleconverters (both this 2x MC-20 and their 1.4x MC-14) are top quality and work better than any other teleconverters that I've ever used. So, I'm very happy with the results I get with my Olympus MC-20 teleconverter and I highly recommend it. If you understand the tradeoffs that they impose and those tradeoffs are tolerable in order to increase the reach of your lenses, then they can serve a valuable niche in your arsenal of photographic gear.
Just remember: You cannot cheat physics. Because a teleconverter (all teleconverters) reduce the light, enlarge the image circle and introduce more lens elements, you will need your scene to be better lit, your autofocus will be a little slower, the range of your in-camera image stabilization will be reduced a little and your images will be a tiny bit less sharp. But, because Olympus has made its teleconveters (like the MC-20) to its Pro-series standard, they are among the best teleconverters on the market and they are fully weather-sealed.
Verified purchase: YesCondition: Pre-owned