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06-10-2012, 09:32 AM   #1
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Dust resistance prime vs zoom?

Do prime lenses offer more dust resist than zooms?

06-10-2012, 11:28 AM   #2
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In theory, yes. Since there is one less ring on the outside (focus only in the case of modern primes) the system is less prone to air circulation. If the lens is internal-focus, the sealing can be even more effective.
06-10-2012, 01:40 PM   #3
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Any lens that changes its external length when focusing or zooming is pumping air -- and dust. I have just one lens marked as IF, the DA10-17, and it changes length, so it pumps air too. AFAIK the only way to avoid pumping air is to mount a fixed-focus lens. Have fun. You'll probably find that WR and DA* lenses' weather resistance blocks much dust.
06-10-2012, 02:03 PM   #4
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QuoteOriginally posted by RioRico Quote
Any lens that changes its external length when focusing or zooming is pumping air -- and dust.
That's kind of wrong, because you can make the rear element fixed and uber sealed, and you don't compromise the camera. But any lens that changes length will pump air at least through itself.

06-10-2012, 02:14 PM   #5
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The DA*50-135 come close to such a design, it has a fixed rear and front element which are sealed.

But lets face it there are good sealed zoom lenses and prime lenses that suck dust in all the time so yeah, prime might be more sealed but they don't need to be.
06-10-2012, 03:15 PM   #6
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The physical construction of prime lens may well make them more resistant to dust, but this may also be out weighed by more frequent lens changing over say a zoom lens.
06-11-2012, 03:56 PM   #7
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Zoom lenses typically have more lens elements and more groups.
All those glass/air interfaces means more surfaces for dust to collect.

Chris
06-12-2012, 05:11 AM   #8
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Thanks guys!

One of my zooms got a big black dust spot in it. Shows up in pix at wide angle. I'm thinking no more non WR zooms for me. But may be a fluke with this zoom. Can they be cleaned or is it not worth the $$?

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