>>3668423>1000 mm f/3.5That's at least a 286 mm primary element, no matter what size the sensor is.
Not sure about your definition of "small", but it's not small IMHO.
Hell, lenses with 100 mm primaries are allready behemoths.
The only thing you could do is to use a 200 mm f/3.5 lens with a 5x crop factor sensor.
>>3668541Megapixels aren't everything.
Bridge cameras aren't sharp at the far edge of their superzoom lenses and these lenses are also realy slow at the far edge as well.
The P1000 in particular has a 539 mm f/8 coupled to a sensor that only produces crap at ISO 400 and above.
With a cropfactor of 5,57 and 16 MP sensor resolution, the diffraction alone makes sharp images impossible.
And that's fully open at maximum focal length where all abberations are the strongest, meaning it's even less sharp than the diffraction limit.
At f/8 the airy disc diameter is allready 10,7µm while the P1000 has a pixel pitch of 1,34µm.
That cuts the resolution down to almost exactly 1/8 of the sensor resolution or 2 MP equivalent. (yes, that's only a crude approximation but good enough for now)
And that's assuming the lens is absolutely perfect in every way shape and form, wich no real lens is or ever was.
Wich means in real life it's actualy worse than that.
TL;DR that "3000 mm" isn't resolving any more detail at a given distance than other telephoto lenses in the 400-500 mm range.
