Perhaps a misconception about the OMD Weatherproofing

Don't say anything at all, or they say the exact same thing.  The Nikon D4 manual barely mentions it - the only reference to weather is about battery usage.  The Pentax K5 manual doesn't mention the word weather at all.  Quick work with Google shows that Pentax also recommends identical things like Olympus with respect to ensuring weather sealing - such as a hot shoe cap (although Pentax users don't seem to think it is really necessary).

The truth is that no camera manufacturer really wants to provide clear guidance on weather sealing because it opens them up to litigation or warranty claims when a camera fails.  Quite simply it is not in a camera makers best interest to provide clear unambiguous guidance.

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http://jcharding.zenfolio.com/