Review on 📸 VILTROX EF-M2 II Electronic AF Auto Focus Reducer Speed Booster Lens Mount Adapter for Canon EF Mount Lens, compatible with M4/3 camera models PEN-F, GH5, GH4, GF9, GX85, E-M5, E-M10, E-M10II, E-PL3 by Reid Rickerson

I use this little speedbooster for my Blackmagic Pocket Cinema Camera 4K. I like how the crop factor went from 1.9x or 2x with the 4/3 sensor to around 1.33x with the speed booster compared to full frame. I'm used to shooting with APS-C cameras and it gives me slightly wider shots with the same lenses that aren't too different from what I'm used to. wobbles except for a very slight twisting play, which is a bit annoying when zooming/focusing with stiffer lenses, but is usually hardly noticeable in the picture. He seems to be durable. I mostly use manual lenses, but the electronics allow me to control the aperture on my Canon lenses and the display even accounts for the equivalent aperture based on the speed multiplier. I have not successfully used the auto focus or image stabilization features on my Canon lenses with this adapter and my BMPCC4K does not seem to realize that image stabilization is even available for Canon lenses. However, I read on the forum that updating the Speedbooster firmware can enable image stabilization on my camera. Unfortunately, Canon EF-S lenses can't be used with this speed booster - they're designed for a 1.6x crop factor anyway and don't look right at the 1.3x crop equivalent. However, due to the longer flange of the EF-S lenses, they don't physically fit this speed booster or many other EF mount adapters in general. Keep this in mind when planning what gear to buy. A nifty trick I've used is using EF macro tubes (with electronic contacts) on my EF-S lenses so they can be used with a speed booster. and support electronic aperture control. You'll lose focus at distance/infinity due to macro tubes, but EF-S lenses work at this setting in certain situations. The only problem I had was not being able to use any of my lenses wide open. Rokinon Primes, Rokinon Cine DS Primes, Tamron's custom Nikon mount zooms all have a lot of "blustick" where the brighter parts of the image appear blurry and are never sharp when the lenses are opened at maximum aperture. But a small aperture solves this problem, and given the ISO of my BMPCC4K, I'm not worried about light loss due to a small aperture. Build quality is pretty good - the optics of the accelerated lens(es) in the adapter are pretty sharp and don't detract from the image much in my opinion. If you have trouble focusing to infinity with this adapter, the internal glass elements can be smoothly rotated to adjust the distance to the lens/image sensor. This can be done with gentle fingers, no tools are required. All in all a great budget alternative to the Metabones Speedbooster!