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!

I read a good review on the RF 100-400 IS lens and, having already experienced the high quality of the RF 600, decided to give it a try. My initial impression is that this lens will be producing some fine quality images with it's stabilization and lighter weight compared to my EF 75-300 L, especially when chasing butterflies without a tripod. The RF 100-400 can focus much closer to a subject compared to the RF 600 and is a welcome addition to my collection. Thanks

For under $100 this camera does the trick. I didn't want to spend $400 on a premium action cam and I came across this cam. I'm glad I pulled the trigger on it because it is a great affordable action cam. Has tons of features on a responsive easy to use touch screen. The buttons on the side are a nice touch to be able to use with the waterproof case on. The pictures and videos come out surprisingly good for the price point. Sound is ok and could always purchase the external mic if need be. Still playing around with everything to learn new things about the cam, but so far so good.

Returned because I put it on my 100-400 4.5 and lost too many stops.

This is a well made digital night binocular. It has a day range of 1000 meters and night vision range of 100 to 400 meter depending on if your looking for birds to larger objects like people. I was happy to find a 32GB Micro SD card in the binocular. It also has a great case and strap. You will need 8 AA batteries to get up and running. The day light quality is not bad but you really got this for the night vision and it's great. You can see my night vision photo at 30 meters with max IR brightness it looks like I have spotlights on its so bright. This will have no problem at 100 meters. I have not tested it at max night range of 400 meters yet. The photo and video quality is good and you can adjust the resolution to get longer videos or higher quality videos or photos.

I'd originally planned to get the RF 100-500 mm L lens, but it costs nearly $3,000. At well under 20 percent of that price, this is a great value. Sure, it's a little slower and only 400 mm at most, but it's a lot lighter and takes very good pictures. I haven't compared it directly against that L lens, but pictures are comparable to or slightly better than the (e.g.) Tamron 150-600 mm G2 EF, although with less reach (but a delight to carry around). I'm very glad that I bought this (100-400 mm) lens.

Download 100 movies and is only 40 % full could possibly download 400 more movies

Mixed feelings on this. I used it on my 7d mkii with the 100-400 mkii and it worked only okay (no autofocus). However using this with the same lens on my GH5 with the metabones speed booster the autofocus works great.