Dust "proof" vs "highly resistant"

The upcoming 70-200 f/4 IS according to canon description: "These features, together with its water-and dust-proof construction, provide both the performance and portability to meet user demands."

Whereas the 70-200 f/2.8 IS according to canon description: "Constructed to pro standards, this fast zoom is also highly resistant to dust and moisture, too."

Now, to my understanding, something-proof means that unless you break it open, nothing will get inside while highly resistant means that though not likely, it's still possible to get dust and liquids into the lens under usage. Does this mean that Canon upped their quality in sealing or is it a marketing gimmick? (Hoping for the 1st)

Well the 70-200 2.8 IS is supposed to be weather sealed with a filter and a 1D series camera, so the f/4 IS should probably be the same. I wouldn't take it diving but if you fell in water, I think you'd be fine.

I wouldn't call it a gimmick but an exaggeration. It's probably the marketing department misquoting the engineering department. If the zoom and focus rings are connected to any internal parts, there is a way for water to seep in.
"Highly resistant" is probably a very accurate description.

Same specifications on both - ignore the marketing speak. They're both "resistant" and not "proof."

If they were waterproof, you could take them underwater (e.g. submersed) and they're not. They're resistant, which means you can stand out in the rain, snow or sand storm and fire away with abandon (and I've done practically all of the above).

Non-L lenses don't have this feature and it is possible to get sand (for example) into the AF mechanism. I've done this, too.

For weathersealed lenses, use a filter to complete the sealing. A lens hood helps a lot as well in keeping the front glass clear.

grego wrote in post #2100228
Well the 70-200 2.8 IS is supposed to be weather sealed with a filter and a 1D series camera, so the f/4 IS should probably be the same. I wouldn't take it diving but if you fell in water, I think you'd be fine.

The only one needing a filter is the 17-40L I think

malla1962 wrote in post #2102990
The only one needing a filter is the 17-40L I think

All L lenses are suggested to have a filter affixed to complete the sealing, AFAIK. Besides, in the environments you'd likely be shooting in to need the weathersealing, it's just a good idea.

Ok. So it's not actually weather-PROOF, but highly resistant. Does anyone know exactly how resistant it is? If strong winds blew rain onto the lens would it still be ok? If you dropped it into a pond, would it survive?

mxwphoto wrote in post #2104391
Ok. So it's not actually weather-PROOF, but highly resistant. Does anyone know exactly how resistant it is? If strong winds blew rain onto the lens would it still be ok? If you dropped it into a pond, would it survive?

With a 70-200 IS and a 1D, you'd be fine, probably. But you probably don't want to go diving in the pool and photographing the ground.

IIRC there was someone on dpreview a while ago that tested if a 1-Series attached to a 500mm f/4L IS (or some other big lens) would float or not, but that's a different matter.

All effort shoud be made to keep any lens out of inclement atmosphere, regardless of lens designation.
Anecdotal evidence of water(rain or even immersion) resistance etc. one occasionally find on equipment fora is just that....anecdotal and possibly even disengenious.
Lenses such as 16-35, 17-40 and 10-22 are particularly vulnerable to front element water/dust penetration. A screw on protective filter is the answer, a method also sanctioned by Canon in their lens manuals.

another good reason for a filter on something like the 17-40 is this - last week i was taking shots of swan's at the 17mm end and it kept pekking at the lens glad i had a filter on or it would have wrecked the MC on the lens.
Rob.

gyrob wrote in post #2105357
another good reason for a filter on something like the 17-40 is this - last week i was taking shots of swan's at the 17mm end and it kept pekking at the lens glad i had a filter on or it would have wrecked the MC on the lens.
Rob.

Damn, what do you think you are doing? Are you trying to dethrone me as a WA bird shooting expert around here ?

mxwphoto wrote in post #2104391
Ok. So it's not actually weather-PROOF, but highly resistant. Does anyone know exactly how resistant it is? If strong winds blew rain onto the lens would it still be ok? If you dropped it into a pond, would it survive?

I've shot in ridiculous downpours and even a blowing nor'easter on the beach - no issues. You'll have more trouble keeping the front element clear to shoot through than anything else (use a hood and hold the lens facing down). Same thing on the viewfinder (keep your thumb over it when not shooting).

If you dropped it into a pond... Well, I don't plan to find out. It'll fair better than a non-sealed lens at least.

Double Negative wrote in post #2105981
If you dropped it into a pond... Well, I don't plan to find out. It'll fair better than a non-sealed lens at least.

I'd wager that the 'sealed' lens lasts about 0.5 sec. longer than the unsealed lens, if you dove into the water with it attached to your sealed dSLR.

Wilt wrote in post #2106126
I'd wager that the 'sealed' lens lasts about 0.5 sec. longer than the unsealed lens, if you dove into the water with it attached to your sealed dSLR.

Probably... It's just not made for submersion.

That would be sick though. Forget waterproof housings. Go snorkelling with your camera, then walk onto the beach and keep shooting!

One time at EPCOT, err, Epcot - it was so hot out... I put the lens cap on, put my thumb over the viewfinder and walked right into one of those "misting stations" and stood there for a good minute or two. The combo was of course nice and wet. That got some looks. Heh.