This camera comes with an adapter ring for mounting filters. Standard filters and lens caps of size 40.5 MM will fit the E90.
Micro cards can be any capacity, but they need to be rated at minimum U3 or V30 to handle the E90 write speeds. Do not pay much attention to micro-cards advertised "Read" speed, only the "Write" speed is important, and will usually be much lower than the read speed. Do not use "bargain-brand" cards.
Be aware that memory cards are rated in terms of MB/s, megabytes per second, while camera speed is usually given as Mb/s, megabits per second. Be careful not to confuse these terms. One byte is 8 bits.
IMPORTANT: If you choose the highest video resolution and frames per second of the E90, even if the video card can handle that data rate, your computer/display/video player may not be able to play the video. See a typical high data rate here:
TIP: The free program "Pot Player" (safe in spite of the name) will usually play these videos even when VLC will not.
To update the E90 firmware, go to the Yuneec website (USA customers go here: http://commercial.yuneec.com/comm-downloads-e90), download the update file to your computer,
then go here for update instructions: https://support.vertigodrones.com/hc/en-us/articles/115002895973-Installing-H520-System-Updates-Including-the-E90-Camera