Nikon D5200 Equipped with Spotting Scope at 2,625mm Focal Length
I ran across this crazy setup at the Nikon booth at PhotoPlus 2013. This is a Nikon D5200 equipped with the FSA-L2 field scope adapter and the Nikon EDG VR Fieldscope 20-60×85 spotting scope.
This combo produces a 750-2,625mm equivalent field of view on the Nikon D5200 (taking into account the 1.5x crop factor).
Before you go thinking that this might be a cheap way to ease yourself into a supertelephoto kit, think again. The above spotting scope will set you back $6k and the FSA-L2 adapter runs $1k. Even worse, the aperture range starts at f/5.9 at the “wide” end and drops down to f/21 at the full telephoto reach of the scope.
A legit 500mm f/4 lens runs a little over $8k and a 2x teleconverter will set you back $500. While that won’t quite get you to 2,625mm, the DX crop factor puts you at a reasonable 1500mm at f/8.