1200mm Lenses
1200mm lenses are huge, real huge. 3 feet long and 36 pounds huge. If you want to win a photographer's heart, buy him this lens (it'll cost you about $100,000, though). To the right, you see the white Canon EF 1200mm lens and the black Nikkor 1200mm lens. Both cannot focus closer than 50 feet, so these are not good for indoor use. Why not just get a telescope? Because of the incredible coolness factor. You'll need a sturdy tripod to support these monsters, and mobility is a foreign word.With a lens this large, everything feels squished because the depth of field is highly compressed. In fact, even at F11 your depth of field is quite shallow due to the immensity of the glass. If your subject is moving, you'll need at least a 1/1200 shutter speed to freeze the action, a tripod assumed. 1200mm lenses aren't particularly useful because they push the limits of the 35mm mount, magnifying lens defects. They're huge, expensive, and cumbersome. If you're not up to the challenge, get a cheapo Canon EF 600mm ($7500) or Nikon 600mm ($10,000) lens. Consider a set of extension tubes to get closer, though they'll reduce your image quality.
You won't find the Canon EF 1200mm lens in stores, on Amazon.com, or even on eBay; only a couple dozen have been made, and then only by special request. Canon manufactured the last one in 2005. If you really must have a new one, send them your pleas and lots of cash and maybe luck will come your way.
While you could put a Canon EF 1200mm on something as cheesy as a Canon Rebel XTi, to really honor its beauty you need something fancy like a 1Ds Mark III ($7500). The combination looks more like a weapon of mass destruction than a camera. Stay out of trouble with this one.

1200mm.com is for sale. By Richard X. Thripp.