Dust, camera crud

Seanazz

Seanazz

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980
Name
Sean
Edit My Images
Yes
Reviewing some pics today, i noticed some had a mark, lens dust. I didn't show on pics at 2.8, 5.6but at f22 it was there.
Is there any reason why i would show up at certain Fstops.
I've looked at the lens and the mirror and can't see anything.


Any input would be welcome.



View attachment 8529
 
gramps said:
It's dust on the surface of the sensor, it shows up more above f11 - give your sensor a blow with a Rocket Blower, or a wet clean if the blower doesn't move it :)
Click to expand...

Thanks for replying. Will have a go at that.
 
ACW said:
When using f/2.8 the depth of field is very shallow; so although the dust is there, it is basically blurred out.
Click to expand...


Not quite. At wide open apertures, the light arrives at the sensor from all areas of the lens from multiple angles whereas the smaller the aperture size, the closer the light gets to being a point of light.

It's a bit like the way shadows are very distinct on a bright day with no clouds but as soon as the clouds are there to diffuse the light, the shadows get less distinct.

What you are seeing is the shadow of the dust on the sensor.


Steve.
 
Steve Smith said:
Not quite. At wide open apertures, the light arrives at the sensor from all areas of the lens from multiple angles whereas the smaller the aperture size, the closer the light gets to being a point of light.

It's a bit like the way shadows are very distinct on a bright day with no clouds but as soon as the clouds are there to diffuse the light, the shadows get less distinct.

What you are seeing is the shadow of the dust on the sensor.


Steve.
Click to expand...


Thanks, Steve.
 
A quick follow up. Thanks for the advice, the offending crud has now disappeared from the sensor. Cheers.
 
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