Rene Ritchie has a nice comparison of black and white filters in iOS 7 and third-party apps:
“To create the comparison, I took the screenshots posted on Apple.com, isolated the unfiltered image, loaded it into the other apps, applied their filters, and then took screenshots of the resulting images.”
I’ve been working on an iOS 7 app that’s partly about photos, though not actually a camera app, and I always thought it’d benefit from a single great black and white filter. Not as one of a dozen filters, but as the only filter in the app — something strikingly different that would be noticed. iOS 7’s built-in filters and apps like Camera Noir have made me reconsider. Why reinvent the wheel when so much good work is being done on filters by other developers?
Related, the excellent mobile photo workflow by Rands.