MauiMoto Loc: Hawaii

One should avoid changing lenses even with the very best weather sealed lenses. With these less expensive lenses you want to avoid zooming in dusty environments. Every time you zoom in you are sucking air into the lens barrel like a sringe, and pumping it back out as you zoom out. Or just don't worry about it and clean your sensor more often, but enough dirt will eventually affect your AF sensor performance.

Bill P

When you zoom the lens from maximum extension to minimum there's a bunch of air that has to go somewhere. Although round, a lens isn't a pressure vessel, so it goes back into the camera. If well sealed the short to long zoom will suck air into the cameras on its way to the lens, but a poorly or unsealed lens will suck in from all over.

Not a problem with film, but digital another thing.

Elmerviking

This is in my opinion laughable. Air blowing out of the eyepiece while zooming??
Do this experiment:
Put the camera on a tripo
Cut a small piece of thread ( I used flytying, very thin thread)
Hold the thread at the eyepiece and zoom in and out
Does the thread move?
LOL...not an bit!

Still believe in the statement?

MauiMoto Loc: Hawaii

Of course. Air, water, electrons, when forced by a potential, will move following the path of least resistance which, depending on the body, may be the eyepiece.

Elmerviking

Yeah, but Ken Rockwell said that it would blow out of the eyepiece INTO YOUR EYE!

sv3noKin51E

Don't know Ken personally, but reckon he's like the rest of us; give his opinion on photography from time to time, whether anyone agrees with him or not. Much of the time he makes a lot of sense and his site contains a wealth of material that many read at no charge though site expenses are huge. KRs had a good career, can buy any gear he likes/needs/wants, and who wouldn't like to suffer such a similar fate:) Whatever some have said about KR's taste, wry writing style or how he views the art and craft, the information he's passed along to the world has made many strive to make their way with a camera and lens.

I carried a snap-on cover for my 35mm eyepiece, similar to what can be found on Amazon and other places, a VKO Eyecup/Viewfinder, DK-5 Eyepiece Cap replacement, listed for several Nikon models, less than $10, when one isn't actually using the camera/ lens, when air and dust gathers. There have been articles regarding dust accumulation due to telephoto lens bellows type pumping action.

We've always kept the camera clean and either covered with an anti-static cloth or in the case when not shooting but when shooting in dusty locations, it's going to get in.

Saw astronaut Jeff Williams changing the IMAX, Canon and Nikon lenses while watching Nasa/Ustream. There's less dust on the ISS than on earth and were no caps or body covers evident; caps floating off would be a problem. When he removed a lens he pushed it into the cushioned side of the compartment where friction/traction held it. In pre-ISS days before more efficient air filtration was devised for long duration missions, particulate and droplets was a huge problem. The air is apparently more dust-free than ever but has that accumulated odor which astronauts have to adapt to. Astronaut Williams then was shown in a different section, away from the unprotected camera gear where his experiment was forming/enlarging water blobs, injecting colored liquids, then propelling seltzer tablets in and through. I hope they were in the easy-to wipe-down section. The seltzer game sent mist/spray outward in all directions. There have been contamination concerns lately, including mold and bacteria forming in darkened sections as well as when deliveries go up. The video and photography is awe-inspiring but am glad we're shooting down on earth, dust and all. sv

Wallen Loc: Middle Earth

Any lens that extends outward and collapse inward to zoom in and out will act like a bellow and pump air in and out the system. If the sliding parts of the lens is loose, the air would pass thru those gaps accumulating dust in the lens itself in due time. If the lens is better sealed, then it will find a way out somewhere else in the camera. Weather sealed cameras like the D7xxx series and above does not have much holes in it for the air to pass in and out of so it will be concentrated on any hole it can find making it more noticeable.

Wallen Loc: Middle Earth

If the price is right, the eyeblow being there or not, should not discourage one to own the Nikon 18-140 VR DX,
It is a good lens.

Orphoto Loc: Oregon

And this was a fine long since dead topic that did not have an urgent need to see the light of day.

Wallen Loc: Middle Earth

Whose talking about urgency?
I do however, find i find this timely. With the mirrorless Interchangeable lens cameras gaining ground and also folks letting go of their old tools, I see these lens pop up for sale or sometimes on sale. So if the price is good, it is a fine addition for those who still use APS-C DSLR's.