You want more choices of walk-a-round 24-70mm zooms with silent motors? Here's your latest option, but it comes in at a slight higher premium cost that one would normally expect from a 3rd party lens maker like Sigma. Sigma's new 24-70mm f/2.8 EX DG HSM Autofocus Lens now incorporates HSM (Hyper Sonic Motor) - a quieter and speedy AF - with full time manual focusing capability and much superior lens construction. At twice the cost of the previous model, ($1,400 retail, $900 street) does it warrant the upgrade? We dropped by Sigma during PMA 2009 to find out more.