RF15-35mm water ingress

[Deepgreen]

I set my camera up for an astrophotography shoot (used with star tracker) recenty, under clear skies and a dry forecast. However a brief but heavy isolated shower hit in the early hours and my 15-35mm lens acquired a pool of water between the outer and second glass elements. I have tried burying it in uncooked rice as a moisture 'wick' and leaving it in the sun for hours (not excessive heat). The bulk of the pool had gone but a cluster of droplets remained on the central area. A couple of questions - how does moisture enter so readily but is so hard to remove, and can anyone suggest a good method I haven't tried? Currently I have it in a fan oven (!) set to only 40C to try to drive the moisture out with the resultant warmth and low humidity in the oven, and I am monitoring frequently to check for excessive heat. The lens is very warm to the touch but no more so than if it is left in the sun for a while.

 

[Deepgreen]

It's not close but may be worth a try. Nevertheless, I appreciate the information - many thanks.

They have replied by saying they will just send the lens to Canon. Another reputable repairer I have tried says that the various glasses and the diaphram are supplied as one unit, which, if that is the case, why has Canon listed the various elements individually (with separate prices for each one) in their quote to me, rather than as one indivisible unit?