A Kickstarter for about $20 .. I've taken the plunge .. others may like to at their own risk :)
A great idea.
Luxi is a small diffusion dome that fits securely over your iPhone’s front-facing camera. When attached and used with a light meter app, Luxi will help you determine the best settings for your DSLR or other camera so that you can take perfectly exposed pictures.
Read more at the Kickstart page: http://www.kickstarter.com/projects/jamesflynn/luxi-incident-light-meter-adapter-for-iphone
Looks fun. I just do not like to have so fragile and costly light meter.
Well, I understand your criticism, Vitaliy ;-)
But if you already carry one (and have a solid protective frame anyway) it sounds appealing. The existing Luxmeter app (actually more of a spot meter) is not bad, actually. I checked it against a Sekonic and it wasn't more than 1/3 off (less range, of course).
It looks like you're new here. If you want to get involved, click one of these buttons!