[Leica] Electronics vs. mechanics

[LRZeitlin@aol.com]

Vik writes:

<<The "build quality", or more so "longevity" of 

electronics is orders of magnitude different (lower!) than the mechanics 

of the MP.  In 50 years, I bet there will be a bunch of dead useless 

M7's around, but the MP, M3's, M4's, IIIg's, etc will still be firing 

away (if you can buy film).>

The failure curve of electronic equipment is entirely different from that of 
mechanical equipment. There is no reason to suggest that the MTBF of a 
mechanical components will be "orders of magnitude" different from that of electronic 
components. With electronic equipment there is a probablity of failure of a 
few percent at initial turn on or very soon thereafter. If it survives the 
intial burn in, it will generally work perfectly for a very long period of time, 
units failing randomly throughout the total life span. When operated within its 
ratings, the failure rate of electronic equipment is usually independent of 
the number of use cycles. Electronic equipment usually fails abruptly in an all 
or none pattern. It works or it doesen't.

Mechanical equipment tends to fail as a function of use in a slowly 
increasing curve. There are two kinds of failure, abrupt mechanical breakage due to 
some material flaw or overstress, and gradual deterioration because of wear. The 
expected life span is usually given in the number of operation cycles, i.e. 
exposures, of time of continuous use, i.e. operating hours. Failure is usually 
defined as operation outside of expected tolerances. In the jargon of the 
trade, mechanical things tend to fail "gracefully". We can always tell when the 
camera needs repair when the 1 second exposure is 2 seconds, or the film winding 
gets hard or the camera makes "pocketa pocketa" noises instead of a smooth 
click.

The virtue of the Leica mechanical design is that there is enough adjustment 
capability in the various moving parts to bring the camera up to nominal 
performance specs during a CLA. By and large, integrated electronic components 
which fail need to be replaced rather than adjusted. The upside of electronics is 
that they are considerably cheaper than precision machined parts that perform 
the same function. Consequently we may look forward to much lower prices for 
new Leica cameras. 

I have no idea how the electronics of the M7 are incorporated into the 
package but modern electronic design strategy suggests that all the integrated 
circuitry be contained in a module that can be easily replaced without the 
necessity of unsoldering and resoldering a number of wires. If this is the case, then 
the short time to repair might ameliorate any anxiety engendered by knowing 
that your camera could fail abruptly at any time without warning. I lied about 
the lower prices. Just wanted to see if anyone was paying attention.

Larry Z

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