Review Metabones Speed Booster S (micro-43)

Article Index

With a teleconverter, you pull the light rays so far apart that the focal point, and thus the image on the sensor, becomes larger. The greatest advantage of a teleconverter is that a relatively small tool enables you to bring a distant subject closer to you. Disadvantages of a teleconverter are that the lens becomes less bright and that lens flaws become greater. A bad converter makes the image visibly less sharp.


And if you do the exact opposite? With a "Speed Booster," instead of a teleconverter, instead of the magnifying the light rays, you compress them? So that—a wet dream for many videographers—the crop factor of a camera with a small sensor becomes smaller (1.4 instead of 2 for micro-43)?

What you need is a mirrorless system camera and a lens that is designed for an SLR camera with a larger sensor. You thus have the space to place a Metabones Speed Booster between camera and lens. If you use a lens that is designed for a camera with a full-frame sensor on a system camera with a smaller APS-C or micro-43 sensor, you reduce the vignetting on the edges. Lens flaws of the original lens will be made smaller and more light also falls on the sensor, so that you can choose a shorter shutter time when there is low light. A 24 mm f/1.4 full-frame lens becomes a 35 mm f/0.95 lens on a micro-43 camera, with—in theory—a higher image quality than the original! It seems too good to be true. And just as with a teleconverter, the lens quality of the Speed Booster determines the ultimate image quality.


Speed Booster: 0.71 crop factor + 1 stop brighter
600 mm f/6.3 (full-frame) becomes 850 mm f/4 on micro-43

How does a Speed Booster work? It puts a lens ("Focal Reducer") between lens and camera that makes the focal distance of the lens smaller. A smaller image ("Reduced Image") results than with the use of the lens without a Speed Booster ("Original Image"). Because more light falls on a smaller surface, the lens with Speed Booster is brighter than without it.

I appreciate it if you share this: