Living with Photography: Testing the Metabones NEX Adapter

By Norman Chan

Why this $600 lens adapter makes sense.

A few weeks ago, I wrote about the Metabones "Speed Booster", a lens adapter for Sony's E-mount cameras to allow them to use Canon full-frame EF-mount lenses. Adam recently received his and we had a chance to test it out together--our video review will go up very soon. But I wanted to use this space to cover some notes from the tests and discuss lens adapters in general. It's easy to have misconceptions about the abilities of a lens adapter, especially when you're shopping for one on eBay or an overseas Amazon partner.

When camera makers sell you an interchangeable lens camera, they're not only selling you the capabilities of that one camera, but an entire ecosystem of lenses to use with that body. It's an important factor to consider when buying a high-end DSLR, since a lens collection will outlive the inevitable obsolesce of today's camera sensor technology and body designs. You'll spend more on lenses over the lifetime of a camera than the camera itself. In fact, the more you spend on a camera body, the more you may feel incentivized to make the most out of that body with quality lenses.

That's not necessarily the case with compact mirrorless camera systems, which have emerged as both an entry-point for photographers moving up from point-and-shoot digital cameras and companion cameras for those who already have DSLRs and want something more portable. Samsung, Sony, Panasonic/Olympus, Fuji, and even Canon each have their own compact camera systems and proprietary lenses. And whether your goal is to use these mirrorless cameras as a stepping stone to buy into a DSLR system later or as a secondary system, investing thousands of dollars into lenses for just these cameras is a pricey proposition. It's an investment made worse by the fact that even within one company's camera offerings, lenses aren't always interchangeable. Sony's NEX cameras can't natively use the higher-end A-mount lenses, and Canon's EOS-M system can't tap into the large EF family of lenses. At least not without adapters.

That's where adapters--whether official, cheap third-party, and now speed boosting--come in. Most adapters are simple mount-to-mount rings--pieces of plastic that lock one type of mount into another. These, which you can find on eBay for as low as $10 for some mounts, likely come with severe limitations. You may have to cope with no aperture controls, severe frame cropping, and image distortion. These compromises are definitely factors you can work with, as long as you know what you're getting into. They're also why a high-end lens adapter like the Metabones Speed Booster costs $600.

So on to the testing.

Let's start with the claims of the Metabones adapter: it'll mount EF-lenses to E-mount cameras, allow near full coverage of the lens with minimal cropping, grant an extra stop of light (hence the speed boost), and work with aperture and auto-focus controls.

Regarding the mounting--yep, it absolutely works. The adapter locks into an E-mount camera on one end and full-frame EF lens on the other. The connection is very secure, tested with both a 24mm f/1.4 lens and 35mm f/1.4 lens. Going back and forth between E and EF lenses was a little tricky, since I had to be careful about protecting the exposed camera sensor, exposed lenses, and both sides of the adapter. It's not something that most people will do, though, since it's more likely that you'd travel with the EF lens affixed to the adapter for one shoot. In terms of weight distribution, it definitely felt weird with the vast majority of the weight in the lens, given how small the NEX cameras are compared to full-frame Canon DSLRs. This is where the flip-up screen of the NEX-5 came in handy, as it let me balance the franken-camera in a comfortable (and steady) grip without having to hold it up to my eyes.

The photo below was shot with the 24mm lens. With a traditional adapter, this would've been cropped to about 36mm on the APS-C camera.

Next, the speed boost, which is the most buzzed-about feature. The extra stop of light delivered by the adapter is directly related its ability to use the entirety of the lens' focal length. That's because even though we're allowing the same amount of total light into the sensor as a Canon 5D would get, the NEX cameras still have APS-C sized sensors. Through the lens in the adapter, more light is being crammed in to the same amount of space than with a full-frame camera sensor, equating to the extra stop of light.

In the shot below, the batmobile was set is a very dark part of the room. And even though the 24mm f/1.4 is no slouch--it's a $1600 lens alone--shooting at f/1 let me get a sharp image at 1/20 second exposure time. It's truly a strange feeling to see the aperture setting on the NEX's LCD roll down to f/1.

As made clear on the Metabones site, autofocus will work, but it's very slow. With the NEX-5R, autofocus took about four seconds to lock onto a shot, which is not useful for moving subjects at all. And with still subjects, autofocus should be turned off--not even the DMF mode is useful. Stick to full manual focus, because edge detection peaking still works.

I was curious to see if the NEX-5R, which actually has a hybrid autofocus system (both phase-based and contrast-detect) would be any faster than a purely contrast-detect system like on the NEX-F3. Nope, both focus at the same speed. Not too surprising, given that you even need firmware updates for older Sony E-mount lenses for the hybrid system to work on the 5R.

Another caveat is the vignetting that appears around the edge of photos with the adapter, as shown in the photo below. It may look artsy, but it's not always ideal for something like landscapes.

Finally, the adapter produces some very light chromatic distortion (or chromatic aberration) around the periphery of photos. This looks blended in with the blurriness of bokeh, but a closer look shows that color fringing definitely appears on some edges. It's not as prominent as on poor quality lenses, but just something to consider.

So the Metabones Speed Booster really does what it advertises. And even though it's $600, it definitely makes sense if you have an NEX camera and know for sure that you're going to upgrade to a Canon DSLR in the future (or conversely, already have EF lenses and want to pick up a NEX). What the Metabones adapter doesn't do is let you replace your 5D with an NEX. A full-frame sensor is still a full-frame sensor, meaning it's still going to give you better definition photos than an APS-C sensor.

When you compare the two shots below--the first from the NEX-5r and the second from a 5D Mark III--the latter photo retains more detail (look at the door) even though both are using the same lens at very similar settings. But that's not an apples-to-apples comparison; the 5D Mark III is more than three times as expensive as the 5R.

Sony NEX-5R w/ Metabones Adapter and 24mm f/1.4 (effective f/1)

Canon 5D Mark III w/ 24mm f/1.4

Below is my favorite shot from the shoot. It's my pick of the week, and please post your own favorite recent photos in the comments below (bonus if they're shot with an adapter!)