Canon 1200/5.6L USM
Need something longer? A Canon Extender EF 1.4x boosts the beast up to a 1680/8, and the Canon Extender EF 2x will get you to a 2400/11. For what it’s worth, if you couple this lens to a Rebel XTi or EOS 40D you end up with the 35mm-equivalent of 1920/5.6, a 2688/8 with a 1.4x extender, and a 3840/11 with a 2x extender. If you need to focus any tighter to your subject you’ll have to hop a plane and fly there.
It’s a good thing I don’t have that much money floating around or I could be a danger to myself.
Stopped down to f/8 and f/11 it’s actually quite remarkable. How remarkable? From midtown Manhattan we were able to read the street signs on the corner of JFK Boulevard East and 43rd St. in Weehawkin New Jersey when viewing image files at pixel resolution. It’s important to keep in mind when you are shooting images of objects literally a mile away or further you start contending with haze, smog, and heat radiation that can greatly diminish the image quality of the best optics, especially during warmer months.