DaveG40
enthusiast
Reged: 21/07/2007
Posts: 245
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Can anyone please explain how dust gets onto a D-slr sensor even though a lens has'nt been removed for weeks. i.e one minute you have a clean sensor and the next dust appears, even though you have'nt removed the lens  .
The lens in question is a Tamron 55-200 and reading several user reviews for other lenses, it would seem that this is'nt a unique experience, with the lens getting the blame.
Any ideas please, & if it is a lens created problem, are certain lenses more prone to creating dust than others ?.
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Mark101
addict
Reged: 15/03/2007
Posts: 514
Loc: Lincolnshire
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Simply because unless the camera and lens are high end spec the camera is never air tight. Furthermore, the dust might have already been in the throat of the camera and just happened to fall onto the sensor while you were using the thing.
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Cavyslave
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Scphoto
Little Fruitbat
Reged: 13/11/2005
Posts: 2465
Loc: Birmingham, UK
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Quote:
Any ideas please, & if it is a lens created problem, are certain lenses more prone to creating dust than others ?.
I've read the that lenses* with extending front elements often can draw dust inside the lens and camera. Also it could been a bit of dust inside the mirror chamber just getting drawn into the shutter mech and eventually sticking to the sensor.
* probably not all of them
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Happiness is a Kebab call donor - Pictures/Blog
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beejaybee
Marvin
Reged: 18/07/2007
Posts: 4464
Loc: Really Here In Name Only
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Quote:
Can anyone please explain how dust gets onto a D-slr sensor even though a lens has'nt been removed for weeks.
Isn't there evidence that at least some of the carp that gets stuck to sensors is worn off bits of shutter blind, sound deadening foam from the mirror assembly, etc?
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john_g
Pooh-bah Hoo-ha
Reged: 09/05/2007
Posts: 2423
Loc: Surrey
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Quote:
The lens in question is a Tamron 55-200 and reading several user reviews for other lenses, it would seem that this is'nt a unique experience, with the lens getting the blame.
Then one has to assume that the lens is depositing the dirt. This seems quite possible as any manufactured item can contain debris.
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John
And the day came when the risk to remain tight in a bud was more painful than the risk it took to blossom - Anais Nin.
http://www.flickr.com/photos/john_gass
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Roger_Provins
Made-it Man
Reged: 22/10/2005
Posts: 2814
Loc: Gloucester, UK
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Zoom lenses are air pumps and with it comes dust. It was particularly noticeable when push/pull zooms were the norm as they could be operated quickly and the rush of air through the viewfinder was obvious.
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Rog
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beejaybee
Marvin
Reged: 18/07/2007
Posts: 4464
Loc: Really Here In Name Only
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Quote:
Zoom lenses are air pumps and with it comes dust. It was particularly noticeable when push/pull zooms were the norm
I don't think this is a fair analysis. There are many push-pull zoom lenses where the external volume remains unchanged as the zoom is operated, the air is being pumped between the spaces ahead of and behind the zooming group. OTOH there are lots of rotary zoom lenses which change volume quite dramatically as the zoom ring is operated.
When a lens mechanism is sucking air (and possibly airborne carp) you will tend to find more of the "dust" in the lens than you find on the sensor.
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