push-pull zooms keeing them clean...

as we all know push/pull zooms suck dusk worse than a pensioner with a mint, so I was wondering is there a way of preventing this with some sort of 'sock' at all? I'm thinking mainly about the 100-400L which would be used outside (wildlife etc) therefore potential exposure to elements is greater.
Once dust has got in (an inevitable eventuality) is there a way of getting it out? or is that a short trip to Canon's service centre...?
likely cost? (in the UK...)

lol!!!

I'm interested to hear that answer as well.....the 100-400 is on my short list for next lens

LMAO!!! What a classic line!!!

Sorry I don't know the answer to your question but I nearly spat drink all over my screen when I read that line.

i have had the 100-400 for about 2 years now and used it alot outside in dusty conditions but i still don't have dust inside (knocks on wood)

i always brush the lens clean when i come home with a regular paint brush.

Push-pull zooms and twist-zooms that change length as you zoom are effected by dust in a similar manner. It usually isn't much of a problem, though over a few years, you're bound to get a few flakes of dust inside somewhere. Sometimes, brand new lenses have a bit or two of dust in them.

But a few flakes of dust aren't going to hurt the image. The innards of the lens are well outside the depth-of-field so the dust will not show in an image (as opposed to dust at the sensor which is another story). You'd have to build up a fair coating to start having an effect on image quality.

My thought is to not worry much about it unless it accumulates, which will probably take about 20 years.

Come to think of it, I have a 30 year old Tamron push-pull zoom that never really had a dust problem. I did wear it out though, to the point that the aperture ring would jam up sometimes, and the zoom was extremely loose. Parts wobbled. The rubber grip material was long gone.

I eventually took it out and shot it with the .45.

Ah yes... the push-pull zoom dust myth. I thought it was about time one of these threads came along

Cadwell wrote:
Ah yes... the push-pull zoom dust myth. I thought it was about time one of these threads came along

nothing like keeping one going

My 28-135 has dust inside it. This happened because I use it for taking pictures at gravel rally events where there is a lot of dust in the air. The 28-135 has a twist zoom, but the design causes air to be sucked into it as it changes volume with zooming.

So I want to buy the 70-200 F2.8L IS lens to use for my rally photos - weather sealed and no change in volume when zooming or focusing. I can think of no other way to minimise the dust issues other than buying an internal focussing/internal zooming lens or not using the lens in dusty conditions.

out of interest; I use a mountain bike with front suspension. it is an excellent system (partly because its one of the best you can get) with a double rubber seal system and a foam 'wiper' that collects any muck that gets past the first seal and preventing access through the second...now what I'm wondering is why there isn't something similar like that to prevent excessive dust getting into the workings of such a lens...the push-pull/telescopic action being virtually identical (if you leave out the fact the forks use lubricating oils etc]. so on a pair of £500 ($1200+) forks that take a whole load of punishment (and I certainly try my best) would not a similar system on a similarly priced - and more - lens be a "good thing" to try and reduce dust sucking potential?

how about a rubber sleeve over the top?