Im wondering if any of you may be able to quickly help me out here by telling me what the difference is between this two models of lens:
APO 50-500mm F4-6.3 EX DG HSM
APO 50-500mm F4-6.3 EX RF
I'm aware what RF, FG & HSM means - but I can't figure out (if much) what the differences are.
RF (Rear Focus)
This lens is equipped with a system that moves the rear lens group for highspeed , silent focusing.
DG (DG Lens)
These are large-aperture lenses with wide angles and short minimum focusing distances. With an abundance of peripheral illumination, they are ideal lenses for Digital SLR Cameras whilst retaining suitability for traditional 35mm SLRs.
HSM (Hyper-Sonic Motor)
This lens uses a motor driven by ultrasonic waves to provide a quiet, highspeed AF.
Also, would any of you recommend/not recommend this lens? I'd be mainly using it for aviation, air shows / fast moving jets etc.
Thanks for your help.
[Edited 2007-05-28 18:10:56]