recently ventured into live band photography (in pubs and others) and found out that with the low lighting and limit of my lens, it is very hard to shoot without flash. the biggest aperture i can achieve is F5.6 to accomodate the telephoto range (usually 55-75mm), and therefore a flash is necessary. however, with flash photography, i cannot achieve the type of effects of spotlights present on stage, and often have photos filled with smoke (stage effect) because of the strength of the flash fired at such small details.
i am currently using the setup d40x, sb600 and 55-200 VR. is an aperture value of F2.8 big enough so that i can shoot my flash directly up for light diffusion.? if yes, F2.8 is big enough, what are my choices (must be AFs).? have considered the 50mm 1.8, but it will not reach the telephoto range that i require, and also, it will only manual focus on my camera. won't it be very tough to always have to manual focus, especially when shooting band photography because they're always moving frantically.?