# Lens mounts seals



## Nobody (Jul 19, 2013)

I have just received a Canon EF 100-400mm f/4.5-5.6L IS USM but I noticed the mount is lacking the rubber seal that my EF 28-300mm f/3.5-5.6L IS USM has fitted is this correct?


----------



## insanitybeard (Jul 19, 2013)

My Canon lens brochure does NOT list the 100-400L as 'Dust and moisture resistant', so it is correct, it would not have the seal on the lens mount. I believe neuro has mentioned previously (if I recall correctly) that despite this, this lens does have seals on it's switches and zoom/focus rings.

(cue jokes about the 'dust pump'  )


----------



## Nobody (Jul 19, 2013)

Thanks for taking time to reply and the information.


----------



## silvestography (Jul 27, 2013)

insanitybeard said:


> My Canon lens brochure does NOT list the 100-400L as 'Dust and moisture resistant', so it is correct, it would not have the seal on the lens mount. I believe neuro has mentioned previously (if I recall correctly) that despite this, this lens does have seals on it's switches and zoom/focus rings.
> 
> (cue jokes about the 'dust pump'  )



There was that guy who started a kickstarter for an external rear gasket that you could slap onto a partially sealed lens like the 100-400 to ensure better sealing, but that has since ended (he got his funds), and I have no clue where you'd actually go about buying one. It would certainly be useful on the 100-400 though.


----------



## paul13walnut5 (Jul 27, 2013)

insanitybeard said:


> My Canon lens brochure does NOT list the 100-400L as 'Dust and moisture resistant', so it is correct, it would not have the seal on the lens mount. I believe neuro has mentioned previously (if I recall correctly) that despite this, this lens does have seals on it's switches and zoom/focus rings.
> 
> (cue jokes about the 'dust pump'  )



I prefer jokes about the mould pump.


----------



## neuroanatomist (Jul 28, 2013)

insanitybeard said:


> My Canon lens brochure does NOT list the 100-400L as 'Dust and moisture resistant', so it is correct, it would not have the seal on the lens mount. I believe neuro has mentioned previously (if I recall correctly) that despite this, this lens does have seals on it's switches and zoom/focus rings.



Correct. FYI, my info on the partially-sealed status of the 100-400L comes from Chuck Westfall at Canon USA.


----------



## rumorzmonger (Jul 28, 2013)

silvestography said:


> There was that guy who started a kickstarter for an external rear gasket that you could slap onto a partially sealed lens like the 100-400 to ensure better sealing, but that has since ended (he got his funds), and I have no clue where you'd actually go about buying one.



The more I read stories like this, the more I think it should be called "fraudstarter"...


----------

