I am trying to find a cheap solution for an ultrawide fast lens on micro four-thirds. I already own a manual speed booster with a reducing lens and aperture blades. I'm looking to create a full frame equivalent of 15-30mm and a max. aperture bigger than f2.8.

Considering all things manual, is it better to use a wide full frame lens with a speed booster on a µ4/3 camera, rather than a native lens? µ4/3 lenses are rather expensive for me (I'm talking above US$500), considering the additional stop of max. aperture that I gain with the adapter?

I know that the question is rather generic, but I'm having fun filming on the cheap o_0

  • \$\begingroup\$ Please define "better". Are you primarily concerned with the absolute best image quality possible? The lowest cost? The "sweet spot" between IQ and cost? Something else? \$\endgroup\$
    – Michael C
    Commented Dec 20, 2021 at 11:36
  • \$\begingroup\$ I'm extremely happy with the Olympus 7-14 in terms of quality, but it wasn't cheap. Far sharper than my Rokinon full-frame primes, which don't really get good in my experience until 35mm and longer. Then again, it's conceivable I just had bad luck of it draw with Rokinon. \$\endgroup\$ Commented Mar 15, 2023 at 3:27

1 Answer 1


It's better to get the native lens. Because you will never find a low-cost 15-30mm equivalent rectilinear lens for MFT in full-frame glass.

You do get, that even with a speedbooster at x0.71, that with MFT crop factor, you are looking for 7.5-15mm/0.71 => 10-20mm lens, right? The smaller your sensor format is, the more difficult it will be to adapt full frame glass to go wide on it. 25mm is normal on MFT. Wide starts at 12. And ultrawide? 7mm.

And those focal lengths only really exist for APS-C digital-era glass, not vintage full-frame (where even 24mm may be hard to find, and 18mm is a prized rarity). And sure in modern digital full-frame glass, Canon makes an EF 11-24 f/4L lens, but it's $3k.

And in my book, the additional stop you get from the speedbooster? Doesn't matter if you aren't actually going ultrawide if that's what you're after.

A native lens like the 7-14 or the Oly 9-18 won't be nearly as big/heavy/expensive as a full-frame lens+adapter. An ultrawide is a more extreme, exotic lens. As such, there really are no super-cheap paths to getting one. Well, maybe the Samyang/Rokinon 12mm f/2 and 10/2.8 lenses. :)

  • \$\begingroup\$ This is exactly where I was stuck, Thanks for the clarification. In fact I was considering the Samyang/Rokinon 12mm f/2 and 10/2.8 lenses, or even Laowa 7mm, as the best options \$\endgroup\$
    – Frikazoid
    Commented Dec 14, 2021 at 18:10

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