So I bought an EOS M and it came with the (seemingly) useless Speedlite 90EX. While it does TTL on the EOS M, my main system is around a Nikon D5200. I am thinking about getting a new manual flash (TTL is too expensive for me) to use off camera with some cheapo transmitters and receivers off eBay. Is there any way to control the flash power on this or will I have to buy a new manual flash (like the Yongnuo)?
Read more: Manually adjust flash power on Canon Speedlite 90EX?