I've used my EF 100-400 with an RF adapter. It's good but as someone older, this RF lens is light, compact, and is optically sound for my purposes. I also own a 150-600 Sigma which usually needs a pod to hold steady and I've missed more shots than I've captured with it. This RF 100-400 is great for me; it so easy to pan while shooting birds in flight!

So far, I’m completely happy I made the move from EF to RF lenses. This lens has performed as expected. No complaints.

I am in no way a professional photographer, but let me tell you, this lens is amazing! I've done so much research and come to find out there aren't many options for the ef-m lens mount, especially to zoom. So i decided to give this one a try and boy am i glad i did. I mean ofcourse unless you want to get the Ef / Ef-s lens adapter.To start off, im using it on a Canon M50 mark II. Yes i know, it's basically the M50 with a new name but honestly it doesn't affect me much, it's the first new camera I've had in YEARS and it works awesome! Second, you will need to make the shutter speed lower and turn off continuous AF and trust me, this will fix all the blurry picture issues. I understand 200mm isn't that far as you would like for wildlife that is pretty dangerous to get really close to but it does its job in regards to animals at zoos or just around your house.The seller was awesome aswell!! I ordered the lens on a Monday morning and had it in my hands by Thursday!! Keep in mind it crossed the whole country and with the pandemic going on it really is a bonus. The description said it was new and was part of a set that didn't sell together, i saved at least $100 for a NEW lens and could not be happier.

Fast lens and very convenient size makes for a very good combination with the Canon EF-M. Louvre

There is a vast collection of EF lenses that can easily be re-used on EFM mounts with this adapter. Works perfectly. Highly Recommended after 2 months of use.

Bought an open box one to save money. Works great! I have a Canon M100 that has been converted to full spectrum and a ton of EF lens. Kept me from buying all new lens and saved money buying used

Really cool and worth the money can use all my EF lens ROKINON LENSES manual cinema prime. You just have to adjust a setting to use manual lens.

Great canon product. It works well with my EF 70-200, EF 300 and EF 400.