Metabones SpeedBooster Ultra vs. Zhongyi Lens Turbo II

[nomad]

Compared the two (IMHO the only ones worth trying) recently on A7's.

 

Right from the start I noticed one big problem with the Lens Turbo: it doesn't fit the A7R II, only my A7S due to the small protrusion covering the lens release on the camera. I suppose you could dremel it down a bit, but not without taking it apart if you don't want metal debris getting into the rear area and later into your camera. The lens is fixed to the camera with a twisting ring, which is nice, since there is no play at all. The front bayonet is very tight, it really needs some force to insert your lens, but again no play.

 

But the bigger problem was misalignment of the whole lens group in the mount: it focuses far beyond infinity (and you loose some range at the near end). It's quite complicated to get at the inner tube to move the whole lens group and even then, you can't get it perfectly adjusted, it only improves to some degree, but the adjustment range is insufficient. While this must not be a deal breaker, you need to keep two things in mind: zooms which are initially parfocal will not be any more with the Lens Turbo and wides angles with floating focusing will loose quite some quality.

 

Apart from these two problems the optical quality is not bad, much better than it's predecessor and the other Chinese knockoffs. Corners are a bit softer than with the Speed Booster, but the center is sharp and the blue dot issue is pretty much gone under all but the most demanding situations (where the lens itself will flare anyway).

 

The SpeedBooster was off quite a bit too when it arrived (both were new). It didn't reach infinity, which is a shame for this price level. But it's adjustment is easily accessible and quite simple: you just loosen one screw and turn the helicoid in or out. After some try and error and narrowing in on the right position it's dead on now for my parfocal zooms and reaches infinity just a tad before the mark (which is normal for most still lenses). It's tight both on the camera and the lens, again no play to speak of.

 

The optical quality is impeccable, very sharp into the corners, just remember that you'll see any weakness of your lenses now (if you've never before seen them full frame). No blue dot problem and no light leaks (they have a recessed and large lens release button, not the usual tiny pin).

 

So, you definitely get what you pay for: if you want to use it with any lenses worth keeping for todays high resolution cameras, the Metabones SpeedBooster is worth it's price.

 

And if you ask yourself why I want to use such a thing on a full frame camera: both the A7R II and the A7S deliver better video when set to APS-C.