The Micro Four Thirds standards group recently posted a warning on its site saying that it can’t guarantee that products made by companies not in the group will work as expected. The message, a link to which is prominently displayed in the site’s top navigation bar, doesn’t name any specific brands or products, but comes at an interesting time for the Micro Four Thirds system.

The official statement says that “the Four Thirds Office does NOT guarantee that products manufactured or sold by non-member companies comply with the Micro Four Thirds System standard or are compatible with individual devices.” It also tells users to check specific compatibility information with the manufacturer or seller of whatever gear you’re trying to buy.

Micro Four Thirds

When we first saw the warning at DPReview, we thought it might be related to the recent GoPro Mission 1 Pro ILS. That camera has a Micro Four Thirds mount, but without any electrical contacts, so most of the lenses for the system from OM System and Panasonic won’t work, since they require those contacts to control aperture and focus.

That’s something potential buyers of the camera should be aware of, and it’s probably the most prominent instance of a product that uses the mount but that’s incompatible with many other products in the system. However, it also seems unlikely that the warning is referring to the ILS: while GoPro wasn’t a member of the group when that camera launched, it has since joined, and the warning explicitly calls out products from non-member companies.

So why was it issued? Honestly, there’s no clear answer. We’re not aware of any major scandals in the Micro Four Thirds world recently, though there have been rumors swirling around Insta360 using the mount for the cameras it’s currently working on. As of the time of writing, it isn’t listed among the supporting companies on the Micro Four Thirds website.

There’s also, as was pointed out several times in a Reddit thread, the case of SG-image, a budget lens company which is also not part of the Micro Four Thirds group. It has released one lens for the system that, according to several reports, doesn’t work at all with older cameras, and has some limitations on several newer models too. However, that lens has been out for a few months, so it would be a bit odd for the group to issue a warning about it only now.

Of course, it’s also possible that it’s just a general message, issued as a standard bit of housekeeping as an increasing number of companies release gear with Micro Four Thirds-shaped mounts without official support. As always, it’s worth reading a variety of reviews before spending your money on a product, especially if you’re going a bit off the beaten path.