The hummingbirds were fussing at me for not having a feeder on my deck, so after getting one, I'm annoying them whenever possible with the K-S1. This is with the FA 100-300 / 4.7~5.8, cropped about as much as I dared:
This is with the Samyang 500/8 T-mount lens left over from my "cheap, long glass" days. I had to put extension tubes on the back to get the minimum focus distance short enough (it's about 10 meters normally, another reason why that lens is so cheap):
And this is with the Samyang 500/6.3 reflector T-mount lens (likewise a cheap LBA buy). The lens is constant-aperture, which at this range gives very shallow DoF. I managed to get the "one eye in focus" look that is so popular in portraits. (@Parallax would be so proud of me!
) I decided it was easier to shorten the MFD on the 500/8 than try to make a Waterhouse stop for the back of the 500/6.3 (if that would even work).