While I have the 40-150 pro with the teleconverter, it just doesn't feel like enough reach sometimes. Olympus has promised us a 300 f4 pro that's compatible with the 1.4x converter and I can't wait for them to release it. Hopefully at a price mere mortals can afford (not $7000 like the ZD300 f2.8). I didn't want to (and honestly cannot) spend big $$$$ on the Canon 500/600/800 f2.8/4s of the world or their Nikon equivalents. There is however the Canon EF 400mm f5.6L USM (isn't that a mouthful?). Universally liked for the IQ and "small" size, and seemingly unchanged from its introduction in 1993 (!!!), the main complaint is the lack of IS and the relatively long close focusing distance (3.5m/ 11.5ft). For us E-Mxx users, that really isn't a concern, is it, what with the great IBIS? I bought a nice used copy of the Canon 400mm to mate to my E-M1 via a plain ol' Fotodiox adapter. With no aperture control, I am "stuck" at 5.6 for the foreseeable future. Initial thoughts: It really doesn't look that big, but it is a heavy lens. I have no trouble with the E-M1/TC/40-150 pro set up and have carried it around for long periods of time with no trouble. The Canon full frame compatible lens is so dang heavy. Wow. Also, I don't have any experience to speak of with manual focus lenses. Having always used autofocus, I was prepared to be frustrated beyond belief. That's the set up. So, how did I do with my toy? Here is a best of collection from yesterday morning's outing to my local riparian. First some random birds: Not looking at you Goldeneye Orange Then, this pretty white Egret. The lighting was great and I got a natural glow in the crook of the bird's neck. Some post processing to enhance the effect: Foggy Of course, no trip of mine to the local riparian is complete without Anna's hummingbirds (these are pictures of at least two different birds). The first couple pictures show the bird sticking its tongue out: Hummingbird 1 Tongue Hummingbird 2 Tongue Hummingbird 3 Rubberneck Hummingbird 4 Gorget Hummingbird 5 Golden light Hummingbird 6 Spreading wings Hummingbird 7 Takeoff Our riparian also has a man-made lake and lots of ducks inhabit this lake: Duck in "painted" water Who knew ducks had eyelashes? I didn't. Eyelashes We all know birds in flight are difficult. Even more difficult, birds pooping while in flight: Bombs away! But, the bird missed the ducks: Missed dang it! Questions, comments, criticism are all welcome. That's how I can learn and get better - please help me get better. Big thanks to @JudyM for helping me while I made this decision.