Olympus M.Zuiko MC-20 600mm

The Olympus MC-20 doubles your focal length for $470 and adds just 150g to your kit. Stabilization is best-in-class at 5 stops, and weather sealing matches the PRO lenses it's designed for. The trade-off is two stops of light, which hurts low light and bokeh. If you shoot wildlife or sports on Micro Four Thirds, this is an easy recommendation.

The MC-20 uses 9 elements in 4 groups, including an HR (high refractive index) lens, and Olympus's ZERO Coating to keep ghosts and flare under control. In practice, that means you're not giving up much sharpness when you slap this between your lens and body. The optical score in our database lands at the 42nd percentile, which sounds mediocre until you remember that teleconverters as a category are fighting physics. Doubling focal length while keeping chromatic aberration in check is genuinely hard, and the MC-20 does it without turning your images into mush.

Autofocus performance is where things get more nuanced. Olympus claims the MC-20 maintains the AF speed and accuracy of the host lens, and our data puts AF at the 54th percentile, right around average for this type of product. That's actually a decent result for a 2x converter, since many competitors slow AF noticeably. But you should know that on the 300mm f/4, you're now focusing at f/8, which can make AF hunt in low light. The 5 stops of stabilization help here, keeping the viewfinder steady enough for the AF system to do its job.

The MC-20 doesn't have many direct competitors in Micro Four Thirds land. Panasonic makes a 2x teleconverter for their Leica DG lenses, but it's not cross-compatible with Olympus bodies in the same way. The Panasonic Leica DG Vario-Elmarit H-ES12035 shows up in our competitor list, but that's a standard zoom, not a teleconverter, so it's really a different product category. If you're on the OM System platform, this is pretty much the only game in town for 2x conversion.

Compared to teleconverters on other systems, like Nikon's Z mount converters or Sony's E mount options, the MC-20 holds up well on build quality and stabilization. Where it falls behind is aperture performance, which sits in the 22nd percentile. A 2x converter on a full-frame f/2.8 lens gives you f/5.6 with much better low light performance than Micro Four Thirds at f/5.6. But those full-frame setups weigh three times as much and cost triple. The MC-20's whole pitch is reach without the bulk, and on that front it delivers.

At $470 USD, the MC-20 is not cheap for what is essentially a metal tube with glass inside. But compare it to buying a dedicated 600mm lens and suddenly it looks like a bargain. The 300mm f/4 PRO plus MC-20 gives you a 600mm f/8 setup for far less than any native 600mm option would cost. In Europe you're looking at 544 to 566 EUR, and Canadian buyers pay 560 CAD, so pricing is fairly consistent across markets.

The value question really comes down to how often you shoot at long distances. If you're a casual wildlife shooter who occasionally wants more reach, this is a smart buy. If you shoot in low light constantly, the two-stop penalty might push you toward a used longer prime instead. For the price of a decent prime lens, you're getting a tool that transforms two lenses you may already own.

The Olympus M.Zuiko MC-20 is a 2x teleconverter for Micro Four Thirds shooters who want to double their reach without doubling their bag weight. It's designed to pair with the M.Zuiko 40-150mm f/2.8 PRO and 300mm f/4 IS PRO, turning them into 80-300mm and 600mm monsters respectively. At 150g and roughly the size of a thick lens cap, it's the kind of accessory you forget is in your pocket until a distant bird shows up.

This thing is for wildlife and sports shooters, plain and simple. If you're already invested in the OM System ecosystem and own one of the compatible PRO lenses, the MC-20 is a relatively cheap way to get serious telephoto reach. The catch is that it costs you two stops of light, so your f/2.8 becomes f/5.6 and your f/4 becomes f/8. That's the trade-off, and it's a real one.

What makes it interesting is the combination of weather sealing, stabilization, and optical design. Olympus claims 5 stops of image stabilization even with the converter attached, which matters a lot when you're handholding what is effectively a 1200mm full-frame equivalent focal length. Our database puts its stabilization in the 97th percentile, which is basically best-in-class for this category.

If you shoot mostly in low light, skip this. The two-stop penalty pushes you to f/5.6 or f/8, and Micro Four Thirds sensors already struggle at high ISO compared to larger formats. You'd be better off saving for a used 300mm f/4 and cropping, or moving to a faster prime. Macro shooters should also look elsewhere, the 27 out of 100 macro score tells you this isn't a close-up tool.

If you don't own one of the two compatible PRO lenses, the MC-20 is useless to you. It's not a universal accessory, and buying it before you have the right lens is putting the cart before the horse. And if you're on a different system entirely, like Sony E or Nikon Z, this obviously won't fit. Look at native teleconverters for your mount instead.

For wildlife and sports shooters on Micro Four Thirds, the MC-20 is close to a no-brainer if you already own the 40-150mm f/2.8 or 300mm f/4. It doubles your reach, keeps autofocus snappy, and adds almost no weight. The stabilization is genuinely impressive, and the weather sealing means you can shoot in rain without worrying about the connection point.

For everyone else, it's a more conditional recommendation. If you shoot landscapes or travel, the 74.8 travel score suggests it's usable, but you're probably better off with a native wide or standard zoom. The macro score of 27 out of 100 tells you everything you need to know about close-up work. This is a specialist tool for getting closer to distant subjects, and it does that job very well.