Was RE: [Leica] DSLR choice - now Zeiss-Ikon

[billgem at hotmail.com (Bill Marshall)]

Some final thoughts on the recent discussion of the uxe of magnesium plating 
on the ZI . . .

Claims were that magnesium is corrosive, which is true. Recent development 
of magnesium alloys have largely eliminated this problem. Some still don't 
like magnesium. Okay.

Let's turn the question around. What about brass? Corrosive?

Well, it's certainly not water proof. Brass is also an alloy - copper & 
zinc. Copper is highly corrosive. It will rust with exposure to even small 
amounts of water within a week. Zinc is also corrosive unless it is 
electroplated. What metal is closest to zinc in chemical composition? 
Magnesium. With proper electroplating, magnesium will be about as resistant 
to corrosion as zinc.

Bottom line is whether these materials will fare well in their intended 
applications, not in an abstract discussion of metallurgy. For its 
application as external cladding on a camera body, magnesium like brass 
(copper & zinc) will do just fine - unless someone tries to use it as an 
underwater camera. Leica agrees with this point, as evidenced by their use 
of magnesium on the Digilux & their description of it as "robust & 
long-lived."

Bill