If the convenience of "iPhone-ography" finds you leaving your SLR camera at home, you may still miss the ability to tweak your shots before they are taken. The Gizmon CPA Filter is a tiny clip-on unit that can reduce light reflection (allowing you to shoot through windows without glare) and increase the sky contrast without affecting the rest of your picture. Those are two tricks that one-touch digital filters can't do. [$25; gizmon.com]