{"action":"created","issue":{"url":"https://api.github.com/repos/waveform80/picamera/issues/231","repository_url":"https://api.github.com/repos/waveform80/picamera","labels_url":"https://api.github.com/repos/waveform80/picamera/issues/231/labels{/name}","comments_url":"https://api.github.com/repos/waveform80/picamera/issues/231/comments","events_url":"https://api.github.com/repos/waveform80/picamera/issues/231/events","html_url":"https://github.com/waveform80/picamera/issues/231","id":94603545,"number":231,"title":"Changing ISO doesn't appear to change sensitivity","user":{"login":"dpcryer","id":13252709,"avatar_url":"https://avatars.githubusercontent.com/u/13252709?v=3","gravatar_id":"","url":"https://api.github.com/users/dpcryer","html_url":"https://github.com/dpcryer","followers_url":"https://api.github.com/users/dpcryer/followers","following_url":"https://api.github.com/users/dpcryer/following{/other_user}","gists_url":"https://api.github.com/users/dpcryer/gists{/gist_id}","starred_url":"https://api.github.com/users/dpcryer/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/dpcryer/subscriptions","organizations_url":"https://api.github.com/users/dpcryer/orgs","repos_url":"https://api.github.com/users/dpcryer/repos","events_url":"https://api.github.com/users/dpcryer/events{/privacy}","received_events_url":"https://api.github.com/users/dpcryer/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-07-12T22:01:23Z","updated_at":"2016-05-03T15:28:30Z","closed_at":null,"body":"Firstly thanks for a wonderful library!\r\n\r\nI'm probably missing something here but don't seem to be able to do much to control the sensitivity of the camera e.g. when I switch exposure_mode=off and then set the ISO to 100 then 400. I was expecting that this would change the analog_gain and digital_gain and therefore the exposure of the preview etc. assuming nothing else is changed. In my testing the preview exposure doesn't seem to change and neither do the values of the gains. I've included the status output from my program (just the values returned by calls to the picamera object)\r\n\r\nexposure_mode set to off, iso set to 100\r\n\r\nresolution:            2592,1944\r\nframerate:             5\r\nshutter_speed:         59984\r\nexposure_speed:        59984\r\niso:                   100\r\nexposure_mode:         off\r\nexposure_compensation: 0\r\nanalog_gain:           83/16\r\ndigital_gain:          141/128\r\n\r\niso then set to 400, no change to analog_gain or digital_gain.\r\n\r\nresolution:            2592,1944\r\nframerate:             5\r\nshutter_speed:         59984\r\nexposure_speed:        59984\r\niso:                   400\r\nexposure_mode:         off\r\nexposure_compensation: 0\r\nanalog_gain:           83/16\r\ndigital_gain:          141/128\r\n\r\nAm I missing something about what iso should be doing and how I should be adjusting the sensitivity.\r\n\r\nFinally is there any way I can read/deduce the iso value when using auto-exposure (in the same way I can use exposure_speed to see what the automatically set value of shutter speed is) e.g. is iso=100*analog_gain*digital_gain?\r\n"},"comment":{"url":"https://api.github.com/repos/waveform80/picamera/issues/comments/216565427","html_url":"https://github.com/waveform80/picamera/issues/231#issuecomment-216565427","issue_url":"https://api.github.com/repos/waveform80/picamera/issues/231","id":216565427,"user":{"login":"lionelhadamar","id":3324123,"avatar_url":"https://avatars.githubusercontent.com/u/3324123?v=3","gravatar_id":"","url":"https://api.github.com/users/lionelhadamar","html_url":"https://github.com/lionelhadamar","followers_url":"https://api.github.com/users/lionelhadamar/followers","following_url":"https://api.github.com/users/lionelhadamar/following{/other_user}","gists_url":"https://api.github.com/users/lionelhadamar/gists{/gist_id}","starred_url":"https://api.github.com/users/lionelhadamar/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/lionelhadamar/subscriptions","organizations_url":"https://api.github.com/users/lionelhadamar/orgs","repos_url":"https://api.github.com/users/lionelhadamar/repos","events_url":"https://api.github.com/users/lionelhadamar/events{/privacy}","received_events_url":"https://api.github.com/users/lionelhadamar/received_events","type":"User","site_admin":false},"created_at":"2016-05-03T15:28:30Z","updated_at":"2016-05-03T15:28:30Z","body":"Hi, \r\nThanks for this library, which is well documented, and easy to use for Raspberry Pi newbies as me.\r\n\r\nI'd like to bump up this question, since I observe the exact same issue on my RPi 3B+ with camera Board v1.3.\r\n\r\nAs Dpcryer noted, it seems not possible to read the ISO value while the camera is in auto exposure mode. (the attribute getter returns the previously set ISO value, hence 0 if in auto exposure instead of the actual ISO value)\r\n\r\nWhat I would like to do is set the camera on auto exposure mode, and then read the actual values of every attributes, and observe how the camera behaves under particular condtions.\r\n\r\nMany thanks for considering this request"}}