Fringer EF-FX vs Metabones Speedbooster EF-FX (with Sigma 150-600)

Started 3 months ago | Discussions thread
OP xaprb Forum Member • Posts: 78
Re: Fringer EF-FX vs Metabones Speedbooster EF-FX (with Sigma 150-600)

I'm going to return this lens to B&H for an exchange. I've done a bunch of testing with it and I believe it's defective. The percentage of the time it refuses to even find focus at all on very easy subjects is just ridiculous. (I mean hunting from near to infinity and back, passing twice through focus without stopping, then showing an error.) I've tried lots of different settings (including those posted by Morris0 here ) and it's just absurdly bad no matter what I do. Half the time it won't even acquire focus on a stationary, well-lit, contrasty subject like a person in a couch across the room. I went on a dragonfly-hunting expedition and gave up and switched to manual focus mode and had better results. I've never had a lens behave so badly.

To add some weight to my theory that it's a defective lens, of the nearly-in-focus shots, almost all of them are front-focused a couple of inches, rarely back-focused. And, some testing of focal plane tilting a la Roger Cicala's method shows a pretty skewed plane of focus. Something's definitely askew, and whether that's the same problem as the autofocus problems or an additional problem, it's not okay.

Hopefully I'll get a better copy in exchange and I'll pick up where I left off and try some more. I also have both the Fuji 100-400 and a Tamron 100-400 on the way for comparison and when I get them (rental) I'll see what they look like in comparison.

 xaprb's gear list:xaprb's gear list
Olympus PEN-F Fujifilm X-S10 Fujifilm XF 23mm F1.4 R Olympus M.Zuiko Digital ED 14-42mm F3.5-5.6 EZ Fujifilm XF 50-140mm F2.8 +5 more
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