So you want to try your old FD lenses? Fine but remember it is totally manual. Yes, we actually had to set everything and focus too. How did we ever get a shot?
Yes the hummingbirds all are cropped, the last one 100%. Yes hand held. Yes a tough target! Yes there is enormous amount of CA. Easily taken care of in PS and/or LR. All shot with a 40 year old lens.
"I wish I could do that."
You can! There is nothing 'special' about me. Hummingbirds do take some extra patience and care, I admit, but anyone can do it. First you need to go out and try. Maybe your first shots don't look great but as you experience shooting you get better. Look over what you got and notice what worked and what didn't. Watch the framing and the exposure and pretty soon, GREAT PHOTOS! Keep in mind nobody gets every shot. Nobody!
One thing I was hoping to show besides the fact of using 40 year old lenses, is you don't need top of the line gear to make beautiful photographs. I admit the old FD 300mm f4L lens has enormous amounts of CA ( chromatic aberration). It took a great deal of processing to remove it in PS. But other than that no extraordinary editing was done to these shots. Lens correction does not exist for this old lens for instance. If you notice the FD 300mm f4 lens was shot at f4, wide open, since the adapter doesn't allow for aperture adjustment. I would not choose f4 to shoot the hummingbirds if I could change it.