Leica M with variable magnification viewfinder

[markmark]

The Leica M cameras come with a fixed magnification viewfinder. What are the difficulties/consequences in making a viewfinder with a variable magnification? Would it be possible? And would it be easier to make a viewfinder with a few fixed magnification steps instead of a continuously zooming viewfinder?

Thanks in advance for your opinions on this.

[richam]

It's been done on the Contax G2, so it's doable, but you might not like the trade-offs. I had the G2 with a variable/zoom finder. The finder was small and difficult to use for older eyes or eyeglass wearers. I sold the G2 largely for this reason. The Leica M is much more usable because it has a large bright viewfinder. If you designed an M with variable/zoom finder and maintain the brightness and size, you are probably talking about a larger camera body. If you keep the M body size, you're probably going to shrink the viewfinder.

[marknorton]

Back in the days when the Leica M8 was the Leica Digital M and we were wilting under the dog days of summer, as Andy put it, waiting for news, we were speculating on what the finder configuration might be. My preference was for a variable magnfication finder to avoid the need for both focus magnifiers and external finders.

In the event, we still need both for lenses wider than 24mm and longer than 35mm. Kind of makes the standard finder a little limited doesn't it? Just 5 of their lenses inside the finder sweet-spot. (24, 2*28, 3*35). Go outside the range, you need to screw in the finder magnifier (and loose the rubber ring) or else attach the Frankenfinder for your framing pleasure.

Sucks, doesn't it?

Problem is, Leica were so broke when the M8 was designed that all they could do was carry forward the finder from the M7. What we really need them to do is stop riding on the back of a barely modified 50 year old design and come up with something better. Of course, it will depend on the sensor size in use but let's say we have an FF sensor, I'd like the finder to provide:

- support for 21mm to 90mm, maybe even 135mm
- variable magnification, 2 or 3 fixed ranges, selected by a lever where the rewind knob used to be
- built in diopter correction

I don't have a problem if the M9 departs from the classic geometry and renders things like the macro adapter (please, drop it!), goggled lenses and Visoflex redundant. We need a finder for now, not one which exists to support old iron which is no longer made.

[markmark]

I've looked through the Contax G2 viewfinder a few years ago. It is indeed smaller than the Leica viewfinder and it also lacks a rangefinder patch (it relies on autofocus).

For the Leica M, I know there is the 1.25x loupe to be attached at the rear side of the viewfinder and some lenses have 'eyes' attached to them that appear in front of the viewfinder and the rangefinder (the 135/2.8 has those I think). I guess it is a matter of building the loupe or the eyes into the viewfinder itself (with an option for activating/deactivating), or providing some mechanism to slide them in front/back of the viewfinder.

I wouldn't mind if it would make the viewfinder extend a bit in front/back of the camera. The advantages would outweigh this drawback I think. You could build fixed magnifications into the viewfinder such that for the 50,75,90 & 135 lenses the same frame could be used.

This would mean (on an M7 for instance):

For the 50mm --> x0.72
For the 75mm --> x1.08
For the 90mm --> x1.30
For the 135mm --> x1.94

Each time you switch to another lens, the framelines in the viewfinder would just stay the same, showing a magnification the same as in an SLR (usually it is something around x0.75 for 50mm with an SLR I think).

And you could the same for a wide angle version. Perhaps you would need two versions of the bodies: the tele-version and the wide-angle version.

It could keep people from wondering whether the telelenses can really be used on a rangefinder camera and could mean more sales of lenses & camera's, making the rangefinder camera more popular. I would surely be interested in something like this.

The Leica M viewfinder hasn't changed since it was invented. I would expect that with the technological advances it should be possible to build something like the above? Or are there optical laws preventing things like this?

[adan]

Markmark: The deal with the M viewfinder is this - it incorporates TWO optical paths, one for the main view, and one for the secondary image that moves in the RF patch.

Any zooming system would have to occur within BOTH of those optical paths, or else the patch image would stay one size while the main image shrinks and grows - making it impossible to align them for focusing.

Which is why the Contax G cameras relied only on AF or indirect, focus-aid "manual" focusing. Manual coincident-image focusing, a zooming viewfinder, interchangeable lenses, and - the compact size and weight that are THE raison-d'etre of the Leica M - are mutually exclusive.

Goggled lenses incorporate TWO lenses on the front for just this reason - to change the magnification of both the main image and the RF patch simultaneously.

The eyepiece magnifier enters the optical chains after they have been joined together by the semi-silvered prism surface in the main finder, so it affects both images equally with one lens.

It should also be noted that the main viewfinder is essentially a solid block of glass (split diagonally for the silvering) that extends from the eyepiece to the front window - there is no air space through which viewfinder elements could move to create a zooming effect internally.

Personally, I use neither the goggled lenses nor the viewfinder eyepiece because they already add too much bulk to an M body.

At some point we must realize that the Leica M is not intended to be an SLR that happens to use a window viewfinder. It is the most COMPACT way of using a certain range of lenses (and yes, IMHO the upper limit for fast general use is 75mm - or 50mm (effective 70mm on an M8). Trying to build it to do SLR things and one just winds up with a big, kludgy "kind-of" SLR that loses most of its RF virtues and is still a horribly inefficient SLR in any case.