It's been really fun to play with this app! Some suggestions

You could say it's personal preference issue, but I'd like to see manufacturer names next to camera models, i.e., Nikon D80 not just D80.

The settings menu has only two items, camera and lens. Suggestion: drop the settings menu as a top-level item, and instead put the camera picker and lens picker as top-level items.

Interaction with the speed, aperture and ISO pickers would be a little nicer if you didn't have to go through so many clicks. Maybe there's a widget you can use that lets you scroll through the speeds, apertures, etc. directly from the main screen. (But without scroll bars.)

The bottom labels "real speed", "real aperture", etc. sit right on top of "store this exposure" buttons, implying that there's a connection between them, which is false.