Just took delivery of these so I thought I would do a quick post. Yes they are a bit on the cheap side (all plastic), yes they are a little lose. I'm not sure I'll use both at the same time because they are just lose enough that the two combined move too much (not even 100% sure I'm going to keep them). They didn't work too well on my Panasonic 45-175 but seem to work well enough on the Sigma 60. But they do AF and they sure do allow for closer focus. http://www.bhphotovideo.com/c/product/971892-REG/vello_ext_mfte_auto_focus_extension_tube.html Olympus E-M10 / Sigma 60mm Lens only Lens + 10mm Lens + 16mm Lens + both Nothing scientific, not even a terrible exciting subject matter. But what the heck.