D80 Strange Spot on Photos

Started Sep 9, 2006 | Discussions thread
desmondism Regular Member • Posts: 188

To check if i have dust on my D70s's sensor, here's what i do:

1. set the kit lens to 50-60mm
2. ISO 200, jpeg-large, to minimize artifacts/noise

3. exposure compensation +0.7 or +1.0; making sure to get a bright picture WITHOUT getting anything blown out

4. aperture priority, set to around f/22 (very small, but not at the lens limit), speed comes in at around 5 sec or longer
5. manual focus set to closest focusing distance

i then shoot a well-lit, plain white wall. i take the picture hand held, making sure i get a blurred shot. i even sometimes rotate the camera or move it slightly fom side to side while the shutter is open, so that the entire frame would be fairly evenly exposed.

if there's any dust on the sensor, it would show up as a dot. bigger specks would make darker dots, but even smaller specks can be found with some inspection. i use the camera's 2" lcd, max zoom and "sweep" the whole frame to look for dots. the very small aperture renders the dust spots sharp enough to be easily seen.

the spot you see in your photo seems to have been blurred because of a relatively larger aperture; try a smaller aperture and take another picture, i think the spot would be more recognizable, and smaller. a previous poster also measured the size of the spot on his picture, but i suppose this size would change with the aperture setting.

this procedure is easily repeatable and after i use a blower on my sensor (with MLU), i take another shot to see if i've removed the dust (or to see if i've introduced more, but that's another discussion) i can also do this pretty much anywhere i have a plain wall (it doesn't necessarily have to be white, but a light-colored backrgound makes it easier to spot the dust).

hope this helps.

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