There is a discussion in the 'Unrequited Gear Lust' forum (http://wetpixel.com/...showtopic=60185) that is especially pertinent to folks here using 45 degree viewfinders on their rigs. The electronic viewfinders on mirrorless cameras are susceptible to being damaged if left in the sun. Like burning a leaf with a magnifying glass. The discussion talks about using a Butler Creek rifle scope cap to protect the optics. The caps flip up for use, then down to protect. The size for the Nauticam 45 VF appears to be 39/30390 and is available from various sources for $8.00 to $20.00.
I cross-posted this here because I rarely view the Gear Lust forum and just happened to stumble on this subject. I thought it would be of benefit to other Mirrorless followers that also usually skip the Gear Lust thread.