Speedlites for film and digital cameras (E-TTL)
These flash units are compatible with all Canon EOS type A cameras that support E-TTL and E-TTL II metering. Some can revert to legacy TTL mode for film cameras. However, the 90EX, 270EX, 270EX II, 320EX, 430EX III, and 430EX III-RT are E-TTL only.
This miniature unit seems like a fairly useless add-on for the tiny EOS M series of mirrorless cameras. It’s powered by twin AAA cells, giving it a very ponderous recycle time. But it has a trick up its sleeve—it can serve as an optical wireless E-TTL master, making it a portable and affordable solution for wireless flash, albeit one with limited range. Canon should have marketed this one as a Speedlite ...