Quote Originally Posted by neuroanatomist


Quote Originally Posted by William
...how hard would it be for Canon to install air filters to prevent this.

They only do that in conjunction with painting a red ring around the barrel.



I have my 24-105 F/4 L one year. I thought, that it is protected from the dust, because of the red stripe and red "L" letter. The dusts is going away, when see lenses with these attributes []. But i was wrong. Several month ago i noticed 2 dusts under the front element. I didn't removed my lens almost 6 or 7 month. And during all the time, that i have, i removed only 2 ar 3 times. Of course, i do not use any protection filter to protect completely, but i think, that the filter is neccesary to protect lens from water drops or if the conditions is really extreme. But in my case conditions was not so dusty (or almost without dust). So..i don't know, how and from which <span class="HW"]junction dust is coming under front element.


[img]/resized-image.ashx/__size/900x0/__key/CommunityServer-Discussions-Components-Files/24/7128.Dusts-1.jpg[/img]


[img]/resized-image.ashx/__size/600x0/__key/CommunityServer-Discussions-Components-Files/24/5751.Dusts-2.jpg[/img]


I think i will use cleaning technique mentioned by freelanceshots. And then will try to use any filter all the time.