{"action":"created","issue":{"url":"https://api.github.com/repos/waveform80/picamera/issues/200","labels_url":"https://api.github.com/repos/waveform80/picamera/issues/200/labels{/name}","comments_url":"https://api.github.com/repos/waveform80/picamera/issues/200/comments","events_url":"https://api.github.com/repos/waveform80/picamera/issues/200/events","html_url":"https://github.com/waveform80/picamera/issues/200","id":58758671,"number":200,"title":"Question about shutter speed","user":{"login":"Gelu74","id":11178522,"avatar_url":"https://avatars.githubusercontent.com/u/11178522?v=3","gravatar_id":"","url":"https://api.github.com/users/Gelu74","html_url":"https://github.com/Gelu74","followers_url":"https://api.github.com/users/Gelu74/followers","following_url":"https://api.github.com/users/Gelu74/following{/other_user}","gists_url":"https://api.github.com/users/Gelu74/gists{/gist_id}","starred_url":"https://api.github.com/users/Gelu74/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Gelu74/subscriptions","organizations_url":"https://api.github.com/users/Gelu74/orgs","repos_url":"https://api.github.com/users/Gelu74/repos","events_url":"https://api.github.com/users/Gelu74/events{/privacy}","received_events_url":"https://api.github.com/users/Gelu74/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-02-24T15:57:32Z","updated_at":"2015-03-03T08:03:49Z","closed_at":null,"body":"Hi Dave,\r\nThanks for the great picamera woderfull library.\r\n I was wondering whether it is somewhere documented the stop values for the shutter speed in the camera module. In picamera I can set the shutter_speed in microseconds but it seems to me that these are approximated to the closer real shutter speed value the camera supports.\r\n\r\nFor example if I run:\r\nIn [62]: camera.shutter_speed=410\r\n\r\nIn [63]: camera.exposure_speed\r\nOut[63]: 401L\r\n\r\nIn [64]: camera.shutter_speed=401\r\n\r\nIn [65]: camera.exposure_speed\r\nOut[65]: 401L\r\n\r\nboth speeds are equal although the microseconds specified are different.\r\nI was particularly interested in knowing the fastest possible shutter speed.\r\n\r\n\r\nRegards from Spain.\r\nAngel"},"comment":{"url":"https://api.github.com/repos/waveform80/picamera/issues/comments/76902656","html_url":"https://github.com/waveform80/picamera/issues/200#issuecomment-76902656","issue_url":"https://api.github.com/repos/waveform80/picamera/issues/200","id":76902656,"user":{"login":"6by9","id":5822349,"avatar_url":"https://avatars.githubusercontent.com/u/5822349?v=3","gravatar_id":"","url":"https://api.github.com/users/6by9","html_url":"https://github.com/6by9","followers_url":"https://api.github.com/users/6by9/followers","following_url":"https://api.github.com/users/6by9/following{/other_user}","gists_url":"https://api.github.com/users/6by9/gists{/gist_id}","starred_url":"https://api.github.com/users/6by9/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/6by9/subscriptions","organizations_url":"https://api.github.com/users/6by9/orgs","repos_url":"https://api.github.com/users/6by9/repos","events_url":"https://api.github.com/users/6by9/events{/privacy}","received_events_url":"https://api.github.com/users/6by9/received_events","type":"User","site_admin":false},"created_at":"2015-03-03T08:03:49Z","updated_at":"2015-03-03T08:03:49Z","body":"The sensor sets the shutter speed as an integer number of lines read out, hence the rounding. The time taken to read out a line varies based on mode, but the 5MPix mode takes 29.5usecs per line.\r\nMinimum shutter speed appears to be 6 lines, or 177usecs.\r\n\r\nBTW Best to ask these questions on the forum (http://www.raspberrypi.org/forums/viewforum.php?f=43) as that is where those who know about the firmware lurk. Picamera is waveform80's wrapper around the GPU firmware."}}