i have a D90 with the 18-200mmVR2 lens.
im looking for something with bigger reach, primarily for sporting events, airshows and nature photography.
i understand that i should probably be asking for 3 lenses for the best for each but i can really only justify 1 lens.
my question is 2 fold...first should i consider a teleconverter...which one, why and what are the benefits/negatives when attached to my camera and lens.
i understand that they give extra reach, are cheaper than a lens (generally) and in the negative increase aperture, thus slowing down the camera.
as for lens im looking at a number of options and would like your feedback from your experiences.
first up nikon 70-300vr, ($500)
sigma 50-500 os, ($1700)
sigma 150-500 os, ($850-900)
sigma 120-400 os. ($750-800)
all have stabilization and sit at about f4-6, so they're not super quick, but i cant afford the super quick f2.8 lens.
from what ive read within the forum, members with each of the above lens all swear by them, but my confusion lies in which one would be best for me, or do i go with a teleconverter?