The single speed shutters on these type of cameras (that would be most rollfilm cameras with one "instant" shutter speed) vary slightly, but most are around 1/30. They were made for films like Verichrome, that had a very wide exposure latitude. Since the only films made in 127 (as far as I know) are all 100 speed, you should do fine on any sunny day. Just shoot it and have fun. Old cameras are a gas! Old Stuff