Sand in mi WR lens

That ad specifically shows a 18-135 WR lens covered in water and says "... worry free use in any weather conditions ... ... to dry dusty or sandy".

Given that a camera needs to have a lens attached to make it usable it is reasonable to expect that a lens of the quality shown would be able to withstand the environment.

The 18-135 is a DA WR and so is the 18-55 ... on that basis it would be reasonable to assume the lens could cope with the sandy conditions - although maybe not a shower afterwards.

Talk to SRS but don't expect an immediate result - it will probably need escalation to Pentax and at that point you should start a robust discussion.


I will add that if a WR lens lets in sand then there is no hope of it withstanding rain!

I've already used the description as detailed in the lens instruction book that comes with many DA lenses: "WR lenses have a simplified weather resistant construction which makes it difficult for water to enter the lens"

I find drinking Red Bull helps prevent sand getting in my lenses. I float slightly above the beach with the down draft blowing sand grains away from the lens.

"Difficult for water" - the sealing must be adequate to stop the easy progression of water. Water can flow at 1 molecule thick in perfect conditions but with surface tension and impurities the layer of water will be tens of molecules thick. So, allowing for 1000 molecule thickness, with a molecule being around 0.3nm in diameter, then the water would be around 0.3 μm thick.

A grain of sand will be less than 1mm - say 0.3mm that is 1 million times the size of a water atom and certainly if sand could enter then there is no chance that the sealing would stop water or dust. How much dust do you expect to see on the inside of a modern lens?

A standard quality single O-ring seal will normally provide sealing to 2 bar and that is from commercially available products.

Having designed seals for vessels operating at 2000m using just 2 hi-spec O-rings, I would expect the type used on the lenses to prevent the ingress of dust and sand.