Upload & Sell: On
| p.1 #9 · Zoom lenses pump dust and vapor into camera? Lens fungus? |
big country wrote:
i think it's more of internet folklore than reality.
+12,500 (cause that's how many lenses I take care of).
We remove dust for cosmetic reasons (well, really because a small % of renters freak out when they get a lens with dust in it, convinced it will be visible on their images - it's easier to remove the dust on the front end than argue with them while they're losing their minds on Friday afternoon because they're convinced they're shoot is ruined before they take a picture.)
There are lenses more prone to getting dust inside them, but it's not particularly the push-pull zooms or even zooms. The 100-400 for example gets dust more than the 28-300 L even though they're exactly the same design. I suspect where they are used has more to do with it than anything. But for fun, I pulled the lenses that have had the highest % of copies requiring dusting so far this year. In order (and this is going to surprise you)
Canon 17-55 f/2.8 IS 25% (vast majority in front).
Canon 100-400 IS L 15% (vast majority in front)
Canon 100 f/2.8 IS L 15% (vast majority in the rear).
Nikon 35mm f/1.4 G 15% (all in rear)
Canon 85 f/1.2 15% (vast majority in the rear).
Canon 70-200 f2.8 Non IS 10% (vast majority in front)
Nikon 70-200 VR II 10% (mostly in front)
Canon 70-200 f/2.8 IS L II 10% (more in front)
Being rental lenses, of course, they've probably had much more dust exposure than most individual's lenses would have.
One thing that may also play a part: notice these lenses all have pretty large front elements, either because they're telephoto or wide aperture or both. I suspect that makes it much easier to see internal dust, plus there's more glass surface for the dust to cling to.
I probably should also mention Canon lenses this year are being rented more frequently than Nikon so that may contribute to the difference, but in general all copies are rented with roughly the same frequency - about 1.75 times a month except for Nikon this year, which is about 1.25.