Suggestion to Leica: M240P with Variable Magn. Finder

[FlashGordonPhotography]

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I had an Xpan. I don't remember it having a zooming VF but my memory is sketchy and I only ever had the 45mm lens. I thought it just switched framelines when you switched between panoramic and 3:2 (or between 45mm and 90mm lenses).

 

Yep. It did. When you put on the 90mm a lens snapped into place that magnified the view. Activated by the lens mount, I beleive.

 

On the other hand the Xpan lenses were f4. Maybe the magnifier isnt precise enough for ultra fast lenses..

 

Some smart guy/gal should invent a screw in variable magnifier, ala the 1.4x, but one that zooms.

 

Gordon

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[edwardkaraa]

Yep. It did. When you put on the 90mm a lens snapped into place that magnified the view. Activated by the lens mount, I beleive.

 

On the other hand the Xpan lenses were f4. Maybe the magnifier isnt precise enough for ultra fast lenses..

 

Some smart guy/gal should invent a screw in variable magnifier, ala the 1.4x, but one that zooms.

 

Gordon

 

Exactly. I feel that is possible to be done internally with perhaps a switch in place of the old frame selector, now gone. This is something that is certainly worth considering for Leica.

[pico]

Exactly. I feel that is possible to be done internally with perhaps a switch in place of the old frame selector, now gone. This is something that is certainly worth considering for Leica.

 

 

I look forward to the engineering solution you provide.

 

 

 

 

Sent from my Etcha-sketch.

[edwardkaraa]

I look forward to the engineering solution you provide.

 

 

 

 

Sent from my Etcha-sketch.

 

Actually I was hoping someone of your genius could provide the engineering solution.

[cookedart]

Here's my engineering solution to this problem. Higher magnification viewfinder + higher eyepoint eyepiece. By that I mean make the entrance pupil larger. That way eyeglass wearers can see 28mm framelines and we get. 72x magnification back.

 

See Zeiss Ikon ZM as an example.

[jaapv]

Just bring back the goggles :D

[pico]

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Actually I was hoping someone of your genius could provide the engineering solution.

 

 

Sir, I could not engineer a mouse trap. I do appreciate a good jest.

 

 

 

 

Sent from my Etcha-sketch.

[pop]

Sir, I could not engineer a mouse trap. I do appreciate a good jest.

 

Let the mice be the judges of that.

[edwardkaraa]

Sir, I could not engineer a mouse trap. I do appreciate a good jest.

 

 

 

 

Sent from my Etcha-sketch.

 

LOL

 

Me too

[jaapv]

Let the mice be the judges of that.

I’m sure they would appreciate a badly engineered mousetrap.

[Peter Branch]

It has always seemed to me that the problems in designing a "zoom" viewfinder arise largely from the way the frame lines are generated.

 

If these were computer generated, (the camera has all the information it needs), and then displayed on a small high resolution LED screen reflected in the viewfinder then it might be a lot easier.

 

This way a number of the limitations associated with the optical viewfinder could also be solved.

 

It might actually be no more expensive that the current, elegant but complex, solution to generating the viewfinder frames.

[giordano]

Here's my engineering solution to this problem. Higher magnification viewfinder + higher eyepoint eyepiece. By that I mean make the entrance pupil larger. That way eyeglass wearers can see 28mm framelines and we get. 72x magnification back.

 

See Zeiss Ikon ZM as an example.

 

If you want 0.72x magnification in the digital M form factor, you lose the 28mm frame lines. Simple as that. The only reason for 0.68 is that they had to make the body thicker than a film M's to make room for all the electronic gubbins. The M viewfinder (leaving the RF aside for a moment) is basically an inverse Galilean telescope, and there's a simple trade off between the length of the telescope (i.e. thickness of the body), the size of the objective lens (i.e. the front window) and the magnification: to maintain the angle of view with a thicker body, you have to reduce the magnification.

 

So if you want to propose an engineering solution for 0.72x on the M-240, you need to include a thinner body and/or a larger front window. (I think the Zeiss Ikon front window is a bit bigger than the MP's, to allow its 0.74x magnification).

 

If you also want variable magnification and/or dioptre adjustment, you need to find room for the moving lenses between the back of the eyepiece and the front window - a volume which in all rangefinder Ms to date is pretty much filled with the massive beamsplitter prism that makes the whole viewfinder possible.

 

@Peter: I'm sure that the lack of space is the determining reason why we'll never see a variable magnification optical RVF in the traditional M form factor. If that could be overcome I don't think the framelines would be much of a problem (though it would be nice to have electronic ones that only showed one frame at a time and adjusted field of view as well as parallax with focus distance).

 

There's a useful cutaway view of the M9 RVF here. I found the cutaway in a long discussion that touches on these issues at elrectanguloenlamano: LEICA M9 TITANIUM: PRELIMINARY ANALYSIS

[wlaidlaw]

All I think we need is an improved version of the Japan Exposures variable diopter eyepiece. I would not mind if it was a fraction bulkier, if that gave improved optics and zero magnification would be nice as well. Surely with all the modern optics tools at Leica’s disposal, this should not be beyond them. I have stopped using my 1.15X Japan Exposure magnifiers, as I found the metal eyepiece with the two grooves to adjust the diopter, scratched my glasses.

 

Wilson

[cookedart]

If you want 0.72x magnification in the digital M form factor, you lose the 28mm frame lines. Simple as that. The only reason for 0.68 is that they had to make the body thicker than a film M's to make room for all the electronic gubbins. The M viewfinder (leaving the RF aside for a moment) is basically an inverse Galilean telescope, and there's a simple trade off between the length of the telescope (i.e. thickness of the body), the size of the objective lens (i.e. the front window) and the magnification: to maintain the angle of view with a thicker body, you have to reduce the magnification.

 

So if you want to propose an engineering solution for 0.72x on the M-240, you need to include a thinner body and/or a larger front window. (I think the Zeiss Ikon front window is a bit bigger than the MP's, to allow its 0.74x magnification).

 

The rear window (the eyepiece) is significantly larger on the ikon.

 

[giordano]

The rear window (the eyepiece) is significantly larger on the ikon.

 

http://i32.photobucket.com/albums/d41/weekschris/zm%20blog/zm-m7-viewfinder.jpg

 

Yes. But AIUI Zeiss did that to allow better eye relief. It doesn't affect the trade off between field of view, magnification, body thickness and window size.

[cookedart]

Yes. But AIUI Zeiss did that to allow better eye relief. It doesn't affect the trade off between field of view, magnification, body thickness and window size.

 

My suggestion still stands though. I don't think its impossible for leica to increase the magnification of their finder just because the body is thicker. I'm sure they've kept the .68x magnification as a halfway point between a .58 and a .72 for usability, not necessarily because it is the only magnification factor possible. If they increased the eyepoint and magnification at the same time, everyone would benefit. Yes this would require new optics. But I think its a better engineering solution than a zooming finder, which would surely be darker.

[giordano]

My suggestion still stands though. I don't think its impossible for leica to increase the magnification of their finder just because the body is thicker. I'm sure they've kept the .68x magnification as a halfway point between a .58 and a .72 for usability, not necessarily because it is the only magnification factor possible.

 

You're right that the thickness of the body doesn't limit the possible magnification. If they chose, Leica could perfectly well fit a 0.91x or 0.58x finder into an M240. What the extra thickness does is reduce the overall field of view of the finder at any given magnification. Using 0.72x with the thicker body would have made the 28mm framelines even harder to see than they are on film Ms. So Leica had to use a smaller magnification. It's an interesting speculation, perhaps, whether they originally chose 0.68x because it permitted 24mm framelines on the M8 and retained it because it also worked for 28mm framelines on the full frame cameras - or whether they decided in advance that 0.68x was needed for 28mm on full frame cameras and kept things simple by introducing it on the M8.

 

If they increased the eyepoint and magnification at the same time, everyone would benefit. Yes this would require new optics.

 

...and a bigger front window...

 

But I think its a better engineering solution than a zooming finder, which would surely be darker.

 

Yes, and even bulkier.

 

I wonder if we'll ever see a 21st century redesign of the mid-20th century M RVF. I hope so - but suspect that Leica may feel that it's not worth the effort in the face of ever-improving EVFs and AF.

[cookedart]

You're right that the thickness of the body doesn't limit the possible magnification. If they chose, Leica could perfectly well fit a 0.91x or 0.58x finder into an M240. What the extra thickness does is reduce the overall field of view of the finder at any given magnification. Using 0.72x with the thicker body would have made the 28mm framelines even harder to see than they are on film Ms. So Leica had to use a smaller magnification.

 

Which is why I suggested that Leica offset this by making the eyepoint/rear window larger. This in effect allows the viewer's field of view to be wider.. or put another way, it allows you to more easily see the edges of the viewfinder, thus countering the effect of a longer magnification. I don't think it necessarily requires a larger front window, since there isn't a lot of space to do that. There however is a lot of space on the rear of the camera to design a larger entrance pupil (look at how much space the rear glass actually takes up vs the height of the top plate).

 

I'm sure Leica hasn't touched it to stay in keeping with their older accessories and to keep the same "feel" as earlier cameras. This however is one improvement that I would love to see, possibly more than an integrated EVF/OVF solution like the Fuji X-Pro 1, mainly because it would benefit all users.

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Hallo,

Look here: Leica M

[luigi bertolotti]

Anyone knows what are the construction differences between the 3 viewfinders available for the M? How complex are these things anyway? Voigtlaender offers 3 magnifications as well for its RF cameras. The wider one has frames from 21 to 50.

 

Maybe it would have already been done if it was easy. Or maybe no one thought of it?

 

The difference between the 3 magnifications on a la carte VF is quite simple : basically 2 optical elements that are different, : one in the main VF assembly, the other is the one (or maybe two) that enlarge the image projected from the small RF window : the whole assembly is exacting the same.... making all of it a zooming apparatus I think would be a mess... costly, bulky, and with less clarity of vision.; personally, I stand with my idea that hybrid is the future... when quality will be up to Leica expectations.