I'm a relatively experienced (enthusiast) topside photographer, mostly landscapes and travel/people photography. While in Bonaire over the past two weeks, I had the joy of borrowing an older Canon A570 in polycarbonate housing for a few snorkels, coming away with some pretty decent shots. All that did, unfortunately, is get me thinking about underwater housing options and seriously considering buying! Particularly as the Galapagos are likely on the menu for this summer. I'm curretly in a bit of a conundrum, and would appreciate any feedback folks can give me.
Gear: I own a 5DII, 17-40, and assorted L glass (none particuarly suited to underwater other than the 17-40). The cost and bulk and fact I don't dive that often lead me to rule this out as my underwater rig. I 'migrated' towards the Oly E-M5 about a year ago, and I'm trimming the Canon rig to the 'essentials', and may reduce it down to just a set of fast primes. While it can't match the Canon, it's close, and it's so, so much smaller and ligher that it makes backpacking with a full range of gear fun again, making it my ideal travel setup. I currently have the Panny 7-14 and 12-35, which might suitable underwater glass, as well as the 'kit' 12-50, which is versatile but slow and not terrible 'special'. My 'pocket camera' for when I don't want to take any bags along is the Sony RX100, which I'm growing to appreciate more and more.
The issue: I want to pack light. Right now, given the limited amount of scuba I do per year, I figure I can rent strobes at most sites more cost-effectively than buying and shlepping. I also very much enjoyed shallow water shots, natural light landscape, and so forth, and will snorkel more than I dive for practical reasons.
The question boils down to 'suit up' the RX100 or the E-M5.
Pros for the RX100: smaller, ligher setup. Cheaper ($1400-1500 with a nauticam, acquapazza or recsea housing and UW wet lens, 1800-1900 if I add a macro diopter). Higher resolution. More verastile (wide to macro with wet lenses)
Cons for the RX100: handling is worse/slower, fps lower, less dynamic range, worse higher ISO performance, lens not as sharp as the 7-14 or dedicated macros.
Pros for the E-M5: better ergonomics, better dynamic range, great IBIS, great glass.
Cons for the E-M5: more expensive (slightly; nauticam housing, port for 7-14 and zoom gear is around $2000), quite a bit blukier - particularly the port.
Things I'm not sure of: the size issue seems fairly relative: the RX-100 is more compact, particularly sans 6" dome port, but the weight differences are going to be minimal if I add wet lenses that weigh as much as the lighter housings. Camera and lens weights are a non-issue, as both the RX100 and the E-M5/7-14 travel with me anyway. Any thoughts people have on additional pros/cons, or corrections to my current understanding of what I'll need. I don't factor prices of lensen into the decision, since I'm looking to add a macro at some point anyway for 'topside' photography.