{"id":674,"date":"2007-12-29T22:28:22","date_gmt":"2007-12-29T13:28:22","guid":{"rendered":"https:\/\/regex.info\/blog\/2007-12-29\/674"},"modified":"2007-12-29T22:28:22","modified_gmt":"2007-12-29T13:28:22","slug":"camera-sensor-dust-reference-page","status":"publish","type":"post","link":"https:\/\/regex.info\/blog\/2007-12-29\/674","title":{"rendered":"Camera Sensor Dust Reference Page"},"content":{"rendered":"\n\n
<\/span><\/a>\nMy Sensor Dust Reference Page<\/span>\n<\/div>\n\n

In a recent post about\nsilly extreme macro photography<\/a>, I commented<\/span> that some of the\nsmall-aperture f\/22 shots weren't good for much except illustrating that I\nneed<\/span> to clean my image sensor. Just as a small<\/span> light source like a\nflashlight<\/span> casts a sharper<\/span> shadow than, say, a large<\/span> light source like a\npicture<\/span> window, a small<\/span> aperture lens setting highlights any dust on the\ncamera's sensor by allowing it to cast a sharper<\/span> shadow on the sensor's\nphotosites, yielding noticeable spots in the resulting picture. Some of my\nsilly macro shots had blotchy dust spots on them.<\/p>\n\n

I clean my D200 sensor about twice a year.<\/span> There are many methods one\nmight use to clean a sensor,<\/span> and for some reason debates about them can\nbecome quite lively. I happen<\/span> to use this\npopular method<\/a>, but whatever method you choose, you need a concrete<\/span> way\nto determine just how dirty or clean your sensor is. This is useful both to\nknow when it's time to clean it, and to ascertain the results of a cleaning<\/span>\nyou just performed.<\/p>\n\n

The best way to test your sensor is to take an out-of-focus picture of a\nsmooth<\/span> field of brightness, with a very<\/span> small aperture (high “f” number)\nlens. Common methods are to take a picture<\/span> of a clear<\/span> sky, or of a\nbrightly<\/span>-lit white wall. I generally<\/span> have neither handy, so make my\ncomputer screen white, and use that.<\/p>\n\n\n

As a joke for something I no longer remember, I once made<\/span> a\ndust reference\npage<\/a> that was totally white, except it had a few<\/span> instructions on how to\ntake a test<\/span> shot. Well, it turns out that I return<\/span> to that joke page twice\na year<\/span> when I clean<\/span> my sensor, as sort of a checklist<\/span> of things to do to\nensure a reasonable<\/span> test:<\/p>\n\n

Set\ncamera to lowest ISO and aperture-priority to highest-numbered f-stop (e.g.\nf\/16, f\/22, ...).<\/span> Set lens to<\/span> its highest zoom and manual focus to\ninfinity. From close enough so that only white fills the viewfinder, aim at\nwhite of screen and take a metered<\/span> exposure.<\/p><\/blockquote>\n\n\n

\n

My Tech-Related Photography Posts<\/b><\/p>\n