M4-P compared to M6

Would someone be kind enough to tell me if mine is a zinc or brass top?
Not that I care that much, just curious.

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Hi Peter,

The flashblock is the same used in all M models starting with the M4-2.

Regards,
Robert

peterm1 said:
When I was shooting an M4P regularly I found it liberating. No meter- so what! I found that a hand held meter was fine. A quick check of the ambient lighting was all that was needed in most situations. Open up one stop when moving into shadow and close down one stop when the sun came out from behind clouds. The natural flexibility of color film took care of the rest. Great photographers like HCB who were doing it constantly got to the point where they could pick the correct exposure without needing any kind of meter. To tell the truth the M4P did have some deficiencies. Many, including me found that the flash sync ports would fall to pieces after a few years as they were poorly engineered. This always bothered me as a Leica should not have cheap plastic parts that break - but the M4P did!
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PKR said:
Just a guess.. cost.

I think the brass plates were stamped and the zinc are cast. Tom A. would know for sure.

If the brass plates were machined then cost is an even bigger factor.
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The brass top-plates for most m's up until the late 80's were deep draw dies stamped. Once you had the dies, the cost was low per top-plate - but the dies are expensive - very expensive (easy $80 000 each and you needed 6 of them). The zinc was cast in a centrifuge and just had to be trimmed and cleaned - easy to make in big numbers.
The later M6/M6TTL/MP and M7 are machined (CNC) from solid blocks of brass. Advantage is that you can do "on demand" top and base-plates - and you can change design easily (old style rewind, slanted rewind, engravings etc) Cost per plate is higher, but not significantly so and the flexibility makes it cost effective for "decorative" changes. You can also change material, titanium or a different composition of brass if needed. The top plate come off the machine in almost perfect
shape - all holes drilled and tapped. flanges cleaned and "de-burred". Saves a lot of hand labor.
 
What sort of coatings/paint do the brass/recessed window M4P's have? Mine is well used (cough, slightly beat up!) and the black goes to silver and then the brass is barely visible underneath.
 
I had always thought the change to less accurate frame lines happened with the addition of the extra frame lines in the M4-P.

Is it certain that unmodified M4-P frame lines show the same area as earlier models?

Is it possible that the changed with the viewfinder change accompanying the zinc top plate?

I remember about 12-15 years ago when I was buying and trading some gear that M4-P's with "M6 windows" were considered a bit more desirable. Odd, now that we know more about them.
 
They were chrome (I think) plated under the black. I don't know if that was for wear resistance, or compatibility with the black anodizing.
 
Mark C said:
They were chrome (I think) plated under the black. I don't know if that was for wear resistance, or compatibility with the black anodizing.
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Ahhhh, OK. That makes it even cooler. I have a chrome and a black M4-P! No wonder why I swap film so often! ;):D
 
The black chrome is called Eloxal and is a Leica product. On a brass top plate there is a "strike" of nickel on the brass and this is there to make the black chrome adhere to it. The same process is used on the zinc plate - with additional copper applied. You can strip the black chrome off a brass top - but it can give problems if you want to do it on a zinc plate. The nickel has to be stripped using a special acid and that can "etch" the zinc badly.
As for the difference in the viewfinders of the M4P and the M6 - the size was slightly reduced to allow for the diodes and also for the chrome "backing strip". I have never had a problem with the sizes - and rangefinder cameras are not designed for perfect framing anyway. Coverage depends on the distance you focus on and, when in doubt, give a bit more and crop!
 
I don't think Eloxal is a Leica 'product', rather a standard industrial finish, and called Eloxal only in Germany. The rest of the world call it anodizing. No?
 
V-12, It is a "salt" used in anodizing and I have only seen it in drums with the Leitz logo on it. This does not mean that you cant buy it. It is used for a lot of "non-camera" applications. Sub-marine instrument panels, jet fighter panels as it can be made with very low reflection by surface treatment (bead blasted, sanded etc). It is also very durable and add virtually nothing to the size of the part anodized. It is a rather nasty process, involving hydrochloric acid, cyanide and high voltage.
 
So nickel rather than chrome. It's nice to get the whole story. Thanks Tom. And for clarifying the finder issue; that makes a lot of sense.

I've always been happy with the frame lines on M's up to the M4-2 and get very few surprises in my negs. I think being able to see everything that will be in your picture (even if it is beyond the frame line) makes it work so well. I found the Contax G's more troublesome because of that.

Tom A said:
The black chrome is called Eloxal and is a Leica product. On a brass top plate there is a "strike" of nickel on the brass and this is there to make the black chrome adhere to it. The same process is used on the zinc plate - with additional copper applied. You can strip the black chrome off a brass top - but it can give problems if you want to do it on a zinc plate. The nickel has to be stripped using a special acid and that can "etch" the zinc badly.
As for the difference in the viewfinders of the M4P and the M6 - the size was slightly reduced to allow for the diodes and also for the chrome "backing strip". I have never had a problem with the sizes - and rangefinder cameras are not designed for perfect framing anyway. Coverage depends on the distance you focus on and, when in doubt, give a bit more and crop!
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It is a rather nasty process, involving hydrochloric acid, cyanide and high voltage, Mr. Bond. Ha-ha. Ha ha ha ha ha ha. Now you will die.
 
My first leica was the m4-p
I rarely would use a meter and by not having one you dont think about it as much the red arrows are a bit distracting and if you do alot of street photography a meter is useless.
Id say go for a leica m2 or go with one that feels right in your hands.
Richarddanielson.tumblr.com/
I still have the m4-p its my beater leica
 
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