You know that and I know that...but when one guy notes the superiority of
TWO bodies made by the same manufacturer...they are instantly accused of
bias.

Titanium is hard to cast and hard to machine.

Scott

According to Rita Ä Berkowitz  <ritaberk2O04 @aol.com>:

    Magnesium can be cast to close to final dimensions, with
relatively little finish machining needed.

    Titanium can be nasty to machine.  And it is too high
temperature a metal to be reasonably cast, so it would have to be
machined entirely from a solid chunk of the metal.  And that also can be
quite expensive -- both in materials cost and machining time.

    Both can be nasty if the fine machining chips get too hot, as
both will burn spectacularly -- hot enough to damage the machine tool on
which it happens -- and perhaps the whole building in which it happens.

    I would like to have the titanium body, but I would *not* like
to  be the man who had to machine it to the required precision.

    And whose chain are you yanking there? :-)

    But I agree that the right plastics can be more durable than the
magnesium body.

    Enjoy,
        DoN.

Magnesium is relatively inexpensive and strong and lighter than
aluminum and titanium.
Having said that, old Olympus OM-4T's (titanium) still bring big bucks
on Ebay.
Also, In December 2005, for the first time on record, the automotive
grade magnesium alloy price per cm³ dropped below the A380 aluminum
alloy price per cm³.
P.S.  The day Canon makes any DSLR out if plastic aside from the
entry-level is the day they cede some market share to Nikon.
Definitely not worth it.

More on magnesium:  www.efunda.com
General Information
Magnesium is a silvery-white metal that is principally used as an alloy
element for aluminum, lead, zinc, and other nonferrous alloys.
Magnesium is among the lightest of all the metals, and also the sixth
most abundant on earth. Magnesium is ductile and the most machinable of
all the metals. Magnesium has a protective film to protect against
corrosion, however it is easily corroded by chlorides, sulfates, and
other chemicals, therefore magnesium is often anodized to improve its
corrosion resistance.
Applications
Due to its light weight, superior machinability and ease of casting,
magnesium is used for many purposes such as auto parts, power tools,
sporting goods, aerospace equipment, fixtures, and material handling
equipment. Automotive applications include gearboxes, valve covers,
wheels, clutch housings, and brake pedal brackets. Wrought alloys are
available in rod, bar, sheet, plate, forgings, and extrusions.

I don't care what they use, so much as I care about the results.  I even
have a testimonial:

Last summer, in Colorado, at 12,000+ feet, I was blown off my feet by a
nasty gust of wind, and hit the pavement *camera first*.  More force than
a free-fall.  The lens was smashed to pieces, glass and plastic everywhere.
I put another lens onto the D2x and kept shooting (after I stopped bleeding);
it was just fine.

That's what I want from my camera.  It's been smacked into walls and
tossed around, too, but that was the Big One.  Putting megapixels and
crop factors and high-ISO noise aside, that's a big reason to pay more
for a high-end pro body.  Whatever it's made out of is fine by me.
It works.

This link <http://www.mine-engineer.com/mining/m-commodity-price.htm>
suggests one reason: cost.  Titanium is more than 30 times more
expensive than magnesium (the $1900 quoted on 2 August for a Metric Ton
of Magnesium works out to about 86 cents a pound). I remember hearing a
few weeks ago that the new aircraft being produced, partly civilian, but
mainly for military purposes, have put pressures on availability, too.

ns

cost.

The Mamiya ZD is smaller and lighter than a 1DS MkII. with more pixels
and larger ones at that.
Also, Mamiya 645 body seems to be one body of choice for PhaseOne P30 /
P45 backs - also dslrs.
A IDS MkII is more comparable to an camera like a D50 than it is to a MF
slr with a P45.