craig

With respect to lenses, Oly does offer a 7-14 rectilinear wide angle (14-28 in FF equiv, vs. ~15 - 25 equiv for the Tokina).  Clearly not 'equivalent' as rectilinear vs. FE although covering very similar focal ranges, for similar uses.  And it does have an 8mm fixed FE.  Neither is cheap, the former much more expensive than the Tokina no less, so I'm not trying to claim both equivalent coverage and less expense.  Just offering the info for the OP's consideration.  The missing 100mm macro (aside from Sigma) is clearly a remaining sore void in the Oly world.

Oly has a prime fisheye and the 7-14.  I would think their wide options are fine given no personal experience with them.  It's the macro that bothers me.  A 100mm would be very long on the 4/3 sensor but the Sigma exists for it though I've never seen anyone house the Sigma 105.  The midrange zoom could substitute for the short macro.  I believe the 50, the 7-14 and the 8mm FE could make a good set if you added the 1.4x for macro and possibly the 14-42 for portraits.  It's just that Canon/Nikon offer more options.

It was much cheaper for me to sell my Nikon gear and totally move to Olympus than to just buy a camera and housing + ports.

I've never made any comparisons regarding Nikon vs. Oly prices but, Ardy, you continue to insist that Oly is cheapest while assuming that nothing less than Oly can meet your arbitrary and vague quality standards.  If you don't need "the best" then who's to say that a digicam at far less size and cost wouldn't be good enough?

Oly wins on price, size and weight with its selection of underwater DSLRs. The only place oly loses with Canon and Nikon is in ISO's past 800 which isn't useful underwater in most cases. Lenses? There are plenty of selections for an olympus user.

You are entitled to your opinion on lens selection, but Nikon and Canon win on more than just high ISO.  Nikon and Canon offer better IQ at base ISO as well.

Given the above complement of lenses, I think its being misinformed to say Oly doesn't offer a complete line of underwater lenses.

As I said, you are entitled to your opinion on lens choices but if you think adding a Sigma 105mm (a lens too long for most on 4/3) and a 35mm f/3.5 (that's still a bit long and is slow focusing) is going to sway people into thinking 4/3 is a competitive macro solution I don't agree.  The Oly 50mm and 35mm both have received complaints for their slow focusing and the Sigma 105mm extends massively making it difficult to house (and it is a slow focuser as well).  I believe a 4/3 user would want manual focus with the 105mm and that lens does not switch between MF and AF easily.  Regarding wide angle, rectilinear shooters may be quite happy with the Oly choices but DX shooters have comparable options plus a far superior fisheye choice.  It all boils down to what you mean by a "complete line".

Expense of the pro glass. - There's some excellent topside glass but it comes at a huge price. Even the Sigma options are expensive.

The expense, size, and weight of the entire system needs to be considered as one component is rather meaningless unless it is optional.  Once you add the size, weight, and cost of everything together the differences aren't nearly what's being represented here.  If Oly pro glass is required to get the lens options necessary for underwater, then it's not really optional is it?

contrary to what Craig thinks it hurts like buggery when the 50th wave jars 10+kgs it into your thighs

When have I said otherwise?  This kind of cheap-shot arguing is unwelcome.  The whole suggestion that the Oly is radically lighter than all other DSLRs has already been debunked.  Sorry you had such a hard time managing your Aquatica F4 but it isn't relevant.  Not all Canon and Nikon DSLRs are as massive as an Aquatica F4.

You think comparing an D300 to an E620 is apples to apples though?  How about comparing a D90 or a Rebel Xsi to the E620 instead - even though that wasn't what the original poster was looking at - it's a much more valid comparison.

That depends on your perspective.  I brought up the D300 because it was a divable system that I could weigh and it is actually heavier than a 5D2.  I believe the weight of the Seatool D300 (aluminum BTW) is pretty competitive.  This is the quote I have been responding to:

The money compared to buying an almost obsolete D80 and a housing was 40% less and would have still weighed 50% more.

Taking Drew's numbers for the Oly housing and body, my D300/Seatool combination is comparably light at 3000 grams vs. 2800.  Of course, a D90 or Rebel would be smaller and lighter than a D300 and that would make the claims of 50% heavier even less likely.

For a housed, ported, lensed, strobed DLSR to cover a couple different shooting ranges (macro to reasonable WA), with reasonable IQ for a hobbyist although clearly not the equivalent of FF...Why not?

You've shot down other arguments based on lack of numerical accuracy, but I don't see any numbers offered to support (or deny) this statement.  There's a $1k difference in current body price alone, D300 to E620 right now (B&H).  Considerably more between the 5DII and 620, which was the OP's original 'what if' comparison.  That's a pretty big start.  I can find other bodies in the sub-$600 range from all manufacturers, but only Oly has OEM housings as an additional option.  Haven't priced them out - I'm still strictly a bottom-feeder myself (used gear).

If you define the argument so that anything less than the Oly can't be considered then it will certainly be the cheapest, but by what standard do you assume that only 4/3 can provide a low cost, reasonable alternative to DSLRs?

Tell us what the OP should be thinking a "complete rig" is to compare with and the total dollars will fall out pretty quick.  Assuming "cheapest" was ever the intent, vs. looking for guidance of where on the cost vs performance slope he should be looking to go.

You're not an Oly fan though...we get it.

I don't need to offer advice in order to counter bogus arguments in favor of one particular system.  I believe both Nikon and Canon offer compelling entry-level gear.  I believe a new buyer should consider cameras, lenses, ports, and housings together when making a purchase.  I don't support the idea of buying the cheapest housings in order to control costs.

No, I am not an Oly fan.  It's main claim is its reduced size but that is hardly realized at all underwater.  Everything else about it is a loser compared to the competition except, perhaps, its price.  No doubt they are capable of good quality results.  So are digicams and even a used D100.  If someone wants a new system with interchangable lenses at the lowest price, a 4/3 may appeal to them and it wouldn't bother me.  I just don't like specious arguments and we've seen a lot of them here regarding Oly 4/3.  Right now it's weight savings but in the past it's been other things like superior macro lenses.

I wasn't aware that I had 'exaggerated' the weight differences, just stated them as fact for a typical setup (body, housing, 3x lenses and ports, without strobes) as I mentioned in an earlier post.  And I have made no judgment about weight whether it is a good or a bad thing, just trying to eek out the facts so that personal judgment can be made based on different system setups with a typical set of lenses and ports for a baseline comparison.

You are free to make your own judgment on weight, which is significant for transportation above water and becomes academic underwater, IMO of course !

My weight judgement would be entire travel weight.  That would include all my photography gear.  Ready to dive weight isn't important to me because any still camera is within reasonable range.  The weight of a few arbitrary components isn't interesting but it sure can be misleading.

Size of the rig is of some importance since it effects what shots you can get.  A housed 4/3 isn't really all that different than smaller Canon or Nikon offerings.

It's interesting you think the 4/3 system does not have the full compliment of lenses for underwater use, which ones would be missing that you might like to use that are missing??  (I am genuinely interested?)

It lacks the variety of macro lenses available in Canon and Nikon mounts and lacks the 10-17 fisheye.  The Oly 50mm macro lens provides similar field of view to a 50mm on DX or 100mm on FX but to get more you have to resort to teleconverters.  If I had to use nothing but a 60mm/DX and a 1.4x I'd be unhappy.

That would appear to make the Oly plus lenses plus a couple of ports around 3.5-4Kg, against a 5D2 in a 2.5Kg housing plus ports guesstimate around 6Kg so a 30-40% weight saving around 2-2.5Kg saving.  An Ike housing would be double the weight of the Oly setup.

It makes no sense to compare only a portion of the rigs.  If you care about travel weight then you need to consider everything.  If you care about lug-around weight then you need to compare the rigs ready to dive.  By comparing only a fraction of the rigs you falsely inflate the percentage difference between the two systems (as is intended).  Since 4/3 doesn't offer any advantage in IQ and doesn't offer the lens selection of DX or FX, it appears that dive weight is it's only argument.  It's a shame it has to be exaggerated to even seem significant.

My Seatool D300 with a 60mm macro, Nexus port, Inon 45 degree finder and Seatool dual grip tray comes in at 4.4 kg ready to dive (no strobes or arms).  The D300 is a heavier camera than the 5D2.  The Seatool tray and grips are 450 grams of that so the system without grips is only 4 kg.

What is the weight difference between the two setups when the 4/3 one doesn't even offer the lens that I need for a dive?