For sale is a like new Luxi diffusion dome that fits over an iPhone 5/5s's front camera. This allows one to use a light-meter app as an incident light meter ("Pocket Light Meter" has a special Luxi mode). See the manufacturer's site for more.

I bought this a couple of months ago and used it with my iPhone 5. It works as advertised.

Since I switched to an Android phone, I no longer have a use for it. It's in like-new condition.

These sell for $29.95 plus tax and shipping from the manufacturer. Mine is for sale for $20 shipped. Payment via paypal, US-sale only.