This is a special case. Taken with a spotting scope.

When you add the prism and the 2x camera adapter you lose a lot of light (f/11 only) and resolution but if you need reach it will do the job. This setup gives an apparent FF equivalent of about 2000mm FL. It's true prime focal length is 620mm. Takes a bit of PP to get it to really dance. Taken at about 300 feet?

[sealonsf]

Great capture.