Mike wrote:
> My conclusion is that the reason Magnesium (or an alloy of it)
> was used for this purpose is purely for cost. It is
> comparatively cheap to cast thin sections with these alloys.
Ralf (Engelman) posted the following on the X-star forum. I repost it here since its
relevant in this debate (BTW This method is the same as Canon uses for the EOS-1v):
Ralf wrote:
The following text about the Bronica medium format rangefinder gives some nice
insights in modern camera casing techniques.
Ralf
"A Solid, Appealing Metal Casing and Magnesium Alloy Top Cover.
The RF645 employs a large proportion of metal components in the body construction to
ensure solid structural strength as well as quality feel and handling characteristics.
The front plate which serves as the main body frame and interchangeable lens mount is
die cast, the bottom plate is of brass and the top cover which houses the rangefinder
is of hard, lightweight magnesium alloy. The leading edge magnesium Thixomolding*
injection method is employed to give the casing the hardness of metal and a complex
shape required for this innovative design: one that cannot be attained through
conventional press stamping.
*Unlike conventional high temperature, high pressure die casting, magnesium
Thixomolding is achieved by injecting near-solid magnesium alloy chips into metal
molds, much like the plastic injection molding process. This method prevents
temperature warping and requires little finishing work, thus making it ideal for line
production. Since the injection mold is used, this method also allows for great
freedom of shape in product design."
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