Why form factor changed (bigger) with M?

[jmahto]

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After using Leica III, I like the form factor. What was the reason M became bigger? In terms of features M3 is same except integrated RF/VF. That should add only height not the width!

Am I alone in thinking that Leica III dimensions are close to perfect!

[pico]

21 minutes ago, jmahto said:

Am I alone in thinking that Leica III dimensions are close to perfect!

Back then the average hand size was smaller. 😎

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[TomB_tx]

Besides the combined range/viewfinder, which also has linkages to the bayonet to automatically change frames with lenses, the bright line finder adds an illumination window, and the window needs to handle parallax correction of the frames. Leitz also wanted stronger gears in the rapid lever wind, and the shutter mechanism changes a lot for the non-rotating dial that sets the full range of speeds. The III series had a 0.5 magnification finder, while the Ms had higher magnification, and needed a longer RF base to get focus accuracy for the planned fast lenses. (Combined with the VF they couldn't have the 1.5x mag of III RF.)

However, several of the Japanese clones of the III managed to incorporate some of the new features in the basic IIIc shape (just slightly larger). Nicca made a couple of models with rapid wind lever, and one even had a flip-open back for film loading like the M3 (I'm shooting a roll in one now). Leotax made a rapid wind version that also had a bright line finder (for 50mm), not full parallax correction. Tanack made a near IIIf clone with a swing-open back, and later made a model with a bayonet mount (but nor M compatible).

Canon, of course, had combined VF/RF with their cameras even back in the 1940s, but with a very squinty eyepiece. They later made models with big finders, long=base RF, lever wind, and even built-in meters, and back-loading, but they got quite large as well. Canon even had a prototype VII with TTL meter (according to some sources).The Canon 7, however, made the M3 seem small.

Leica did realize that some users wanted a return to smaller cameras, which resulted in the CL. I heard about plans for that in the late 1960s, although it wasn't marketed until '73.

Edited March 14, 2019 by TomB_tx

[Michael Geschlecht]

Hello Everybody,

Actually, the increase in size was not that great.

A IIIc or a IIIf have a length of 136mm. An M3 (The first "M" camera.)  is 138mm long. +2mm: Not that much. But a small gain in cubic millimeters.

A IIIc or IIIf have a depth of 39mm. An M3 has a depth of 36mm. -3mm. The M3 looses some cubic millimeters because it is not as deep.

A IIIc or IIIf have a height of 65mm. An M3 has a height of 77mm. +12mm. This is significantly more cubic millimeters. But, of course, as it is with the height of the IIIc & IIIf: The height difference of the M3 is significant mostly in the rangefinder & viewfinder section of the top.

Best Regards,

Michael

Edited March 14, 2019 by Michael Geschlecht

[luigi bertolotti]

3 hours ago, jmahto said:

.... In terms of features M3 is same except integrated RF/VF. That should add only height not the width...

 

And that's the point, as precisely evidenced by Michael , and that's also the real big improvement of M3 : a VF that, apart frames, is anyway much more enjoyable : all in all, can be true that IIIc/IIIf size is close to perfect, but anyone can feel how better is the M Viewfinder.

 

[gyoung]

9 hours ago, luigi bertolotti said:

And that's the point, as precisely evidenced by Michael , and that's also the real big improvement of M3 : a VF that, apart frames, is anyway much more enjoyable : all in all, can be true that IIIc/IIIf size is close to perfect, but anyone can feel how better is the M Viewfinder.

 

Very much the point, I bought my M3s because of the viewfinder, still IMHO the best they used in a film camera.   I had previously used a IIf, and now have a III, and they usually are used with either brighline finders or at least a good variable finder, then you lose the height advantage, but gain hugely in pleasurable use. 

Gerry 

 

[willeica]

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The 3 best Leicas for form factor, for me, are the I Model A, the II Model D and the M3. Leica cameras grew in size as features were added and/or improved and there was, and still is, a trade off between features and form factor. The M3 viewfinder has never been equalled on any Leica, but nothing beats carrying a I Model A in your pocket and taking it out to shoot at the 'decisive moment'.

William

 

[wizard]

That is very much a personal preference. Many people who started with a Leica III, as e.g. my father who had a IIIf, never got to like the bigger form factor of the M models (M3, M2, M4), but people like myself, who started with the M models (in my case an M3 in 1973) would never put up with the disadvantages of the earlier III models (screw mount lens attachment, much smaller, non-brightline finder, separate rangefinder window, rewind knob instead of rewind lever, lack of access to the film pressure plate etc.). 

The Leica IIIg in a way was Leica's attempt to provide their loyal III series users with at least some of the advantages of the newer M models, but it was the M that prevailed until today, and for many good reasons.

Andy

[Ambro51]

One can wonder too why the M10 is so large, a digital camera....your phone too a digital camera .....so tiny you can’t figure out where it is.   

[pico]

1 hour ago, Ambro51 said:

One can wonder too why the M10 is so large, a digital camera....your phone too a digital camera .....so tiny you can’t figure out where it is.   

The scale begins with lens size and with anticipated presented image size, the later often greatly overestimated.

[adan]

The combined rangefinder/viewfinder - period.

Imagine trying to see a 135 frameline within the "peep-show" 50mm viewfinder (0.4x magnification) of the screw-mount cameras.

In addition to TomB_tx's remarks:

- In the screw-mount cameras, the rangefinder and viewfinder share some of the same space. Their optical paths cross through one another like a street intersection, thus the window arrangement: circle - rectangle - circle.

/--<--|   |--<--/

- The screw-mount cameras have separate and different magnifications for rangefinding and viewfinding. 0.4x (0.5x in IIIg) for viewing, 1.5x for rangefinding/focusing. To combine those in one M unit and still have a reasonable magnification for focusing required a compromise magnification of 0.91x (M3) for both viewing and focusing at the same time. Which was dismally low to focus a 135 f/4 (soon to come). To compensate, the physical RF base-length had to nearly double, from 38mm(SM) to 68.5mm(M) (38mm x 1.5x = 57mm effective, 68.5mm x 0.91x = 62.3mm effective).

So - the M3 viewfinder window is about twice as large vertically and horizontally, to still frame 50mm and also allow a reasonable magnification for 90/135 framing boxes. And an additional ~30mm extension had to be added to the RF optical path, over towards the shutter button, to keep (or slightly increase) the focus precision. Which happened to also comfortably allow space for the frameline-illumination window.

Of course, since the M3, the VF magnification was reduced again to allow a 35mm "wide-angle" field of view (0.72x = 49.3mm effective base length) in the M2, M4, and following cameras. Just barely enough to focus a 135 (preferably, stopped down a bit for DoF). But the basic form-factor stayed the same until the digitals

[willeica]

Form factor is all about the tactile re-assurance that you get when you pick a camera. It is dangerous to try to over-explain it. My 3 favourites in the form factor stakes are the I Mod A, II Mod D and M3 that I mentioned already. I don't really like having the slow speed dial or a self timer under my right hand, even though I own and like a lot of cameras that have those features. One of the nicest cameras to hold from a right hand perspective is a button rewind M2 with no self timer. It gives the cleanest right hand feel of any Leica camera when held. I still prefer the M3 viewfinder to that of the M2. With a 35mm lens on an M3 you can use goggled versions or better still, if you are not using a Leicameter, an SBLOO in the shoe.

William

[jpattison]

On 3/14/2019 at 7:49 PM, Michael Geschlecht said:

The M3 looses some cubic millimeters because it is not as deep.

They had to provide a way of mounting screw lenses on the bayonet and still focus on infinity. The adapters are only 1mm deep, though.

John

[ph.]

Nothing to add to the size issue, but I really appreciated the frameline "suspended in mid air" if both eyes were kept open.

p.

[Michael Geschlecht]

1 hour ago, jpattison said:

They had to provide a way of mounting screw lenses on the bayonet and still focus on infinity. The adapters are only 1mm deep, though.

John

Hello John,

Correct.

But, the actual difference in depth is 3 millimeters. The M3 is 3mm LESS deep than the IIIf.

And this is on the "shortest" side which means that its volume is measured as a factor of multiplying its depth by the 2 "longer" sides. A significant number when we are writing about weight.

Best Regards,

Michael

[jpattison]

 

3 hours ago, Michael Geschlecht said:

But, the actual difference in depth is 3 millimeters. The M3 is 3mm LESS deep than the IIIf.

Yes, Michael, that's why I said "though" at the end.

John

[pedaes]

I also thought the slightly larger diameter of the bayonet mount helped the lens designers.

[TomB_tx]

4 minutes ago, pedaes said:

I also thought the slightly larger diameter of the bayonet mount helped the lens designers.

Yes, but Leitz made a prototype IIIg with the M bayonet, so it would have been feasible to have that mount on a smaller body.

[pico]

10 hours ago, willeica said:

One of the nicest cameras to hold from a right hand perspective is a button rewind M2 with no self timer.

Is it the lack of the self-timer that makes the difference?

One of mine (picture).

 

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[willeica]

46 minutes ago, pico said:

Is it the lack of the self-timer that makes the difference?

One of mine (picture).

 

Yes and the button rewind is nicer than the lever rewind with a nasty sharp knob on top of it. I never use the self timer on an LTM or M camera, so, for me, it is surplus to requirements. The whole question of form factor is one which is a matter of personal taste, of course.

William