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wilfredo

M9 Frame Lines

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IIRC the distance between them also comes into the equation. In other words you can (within reason) have any magnification you want, or any field of view you want, but as long as you stick to the basic inverse-Galilean design used in all M viewfinders the relationship between the two depends on the thickness of the body.

 

Another smart man in the crowd.

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Or what?

 

Or you will make yourself seem not to smart, as you already have.

 

It is best to let people think you are a idiot then to open your mouth and prove it.

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The magnification is not dependent on the dept/thickness of the body. The Field Of View of the viewfinder along with what the widest framelines that can be seen is dependent on the thickness of the body combined with the magnification of the viewfinder.

 

Interesting discussion, indeed. The above quote of shootist in my view explains the situation perfectly. IF you have a given body depth and IF you want to fit a given frameline, say for 24mm, into the viewfinder, then a certain maximum viewfinder magnification will result which permits to meet the aforesaid two boundary conditions. Lower viewfinder magnications will, of course, be possible, leaving more room beyond the widest frameline. However, any higher magnification than the maximum viewfinder magnification resulting from the two IF's will NOT be possible. It IS as easy as that.

 

Andy

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I'm trying to follow this interesting discussion.

 

Is the window of the viewfinder the limiting factor that determines the tunnel effect? If so then Lars' question about the differing magnifications of 0.5, 0.72 & 0.85 is very valid.

 

Do the different magnifications have different sized windows (tunnels) or are they the same?

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Again, explain why the M7 can have three different finder magnifications!

 

The incorrigible old man from he Age of Evidence

 

 

Because it can, so can/could the M8.

Leica chose the x.68 mag so they could get at least 24mm lens framelines, EFOV of 32mm, in the viewfinder and give you OK to good focusing with lenses from 24mm up to 90mm. They could of lowered the mag to x.58, and included 21mm framelines EFOV of 28mm, but then they would of needed to drop the 90mm lines and getting correct focusing for 50mm and longer lenses would of been hit and miss. They could of also made the M8 VF mag x.72 but then you would only get 28mm, EFOV of 37mm, in the viewfinder.

Leica could, and probably will, offer different magnification in the new M9 or M10, when and if those models ever comes to light, but it will need to be a thinner body then the M8 to make different magnification really usefull.

As it is now if the M9 is FF and the same thickness as the M8 you will probably only see one magnification offered trying to give the users the best of both worlds, long and short FL. What this is no one knows at this time.

But if the M9 is FF and the same thickness as the M8 they will not be able to fit 28mm FF framelines inside the viewfinder if they leave the magnification at x.68. The FF 28mm framelines are bigger, wider and taller, then the 24mm cropped framlines that are in the M8.

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I'm trying to follow this interesting discussion.

 

Is the window of the viewfinder the limiting factor that determines the tunnel effect? If so then Lars' question about the differing magnifications of 0.5, 0.72 & 0.85 is very valid.

 

Do the different magnifications have different sized windows (tunnels) or are they the same?

The tunels, viewfinder distance front to back, on the film M are all the same length physically but different then the M8 (The M8 has a longer tunel) and the windows on the front and back of the camera, Viewfinder, Rangefinder & eye piece, are the same size for any magnification and the same for the M8.

 

By changing the magnification you are changing the perceived tunel length. It's just like mounting a 21mm lens on the camera, very wide field of view, and then changing that out to a 90mm lens, much narrower field of view. The higher the magnification the narrower field of view through the viewfinder. The lower the magnification the wider field of view through the viewfinder.

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I'm trying to follow this interesting discussion.

 

Is the window of the viewfinder the limiting factor that determines the tunnel effect? If so then Lars' question about the differing magnifications of 0.5, 0.72 & 0.85 is very valid.

 

Do the different magnifications have different sized windows (tunnels) or are they the same?

 

The different demagnifications are to counteract the tunnel effect. My favorite Leica VF is the M3 which is ~1x as well the 50mm FL is continuous and thick. Another solution is to make bigger front windows and increase the size of the internal components accordingly. One might be able to have a wider angle of view without as much demagnification. I suspect this is not done in part due to costs. There may also be physical constraints on enlarging components and having it fit in the same space. Note that there are other rangefinder cameras that have been made including larger formats - overall size of the range-viewfinder is quite variable.

Tom

Edited by waterlenz

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Because it can, so can/could the M8.

Leica chose the x.68 mag so they could get at least 24mm lens framelines, EFOV of 32mm, in the viewfinder and give you OK to good focusing with lenses from 24mm up to 90mm. They could of lowered the mag to x.58, and included 21mm framelines EFOV of 28mm, but then they would of needed to drop the 90mm lines and getting correct focusing for 50mm and longer lenses would of been hit and miss. They could of also made the M8 VF mag x.72 but then you would only get 28mm, EFOV of 37mm, in the viewfinder.

Leica could, and probably will, offer different magnification in the new M9 or M10, when and if those models ever comes to light, but it will need to be a thinner body then the M8 to make different magnification really usefull.

As it is now if the M9 is FF and the same thickness as the M8 you will probably only see one magnification offered trying to give the users the best of both worlds, long and short FL. What this is no one knows at this time.

But if the M9 is FF and the same thickness as the M8 they will not be able to fit 28mm FF framelines inside the viewfinder if they leave the magnification at x.68. The FF 28mm framelines are bigger, wider and taller, then the 24mm cropped framlines that are in the M8.

 

Ah! I think I get what you are saying.

 

M8's window will only allow a 32EFOV (24mm lens) at 0.68x because of its body's thickness.

 

While an M7 will allow a 28mm FOV at 0.72x because the body is thinner because the same window allows you a broader view at a higher magnification.

 

So if the as yet mythical M9 is similarly as thick as the M8, a 0.68x magnification can only allow at best the 32mm view?

 

Then a lower magnification (0.68x < is needed ) for a 28mm lens.

 

Would I be right, Shootist?

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The different de-magnifications are to counter-act on the tunnel effect. My favorite Leica VF is the M3 which is ~1x as well the 50mm FL is continuous and thick. Another solution is to make bigger front windows and increase the size of the internal components accordingly. One might be able to have a wider angle of view without as much de-magnification. I suspect this is not done in part due to costs. There may also be physical constraints on enlarging components and having it fit in the same space. Note that there are other rangefinder cameras that have been made including larger formats - overall size of the range-viewfinder is quite variable.

Tom

 

Actually, I would like to have a 1x VF for 50 to 135 FL. It would be great for me:)

 

1 model of rangefinder is quite enough for me, though, much as I enjoy the experience.

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Ah! I think I get what you are saying.

 

M8's window will only allow a 32EFOV (24mm lens) at 0.68x because of its body's thickness.

 

While an M7 will allow a 28mm FOV at 0.72x because the body is thinner because the same window allows you a broader view at a higher magnification.

 

So if the as yet mythical M9 is similarly as thick as the M8, a 0.68x magnification can only allow at best the 32mm view?

 

Then a lower magnification (0.68x < is needed ) for a 28mm lens.

 

Would I be right, Shootist?

 

Yes that is totally correct. You win the door prize.

Thank you for understanding. This forum seems to be a little short on that in this

thread.

 

Actually there is some room outside the 24mm framelines on the M8 viewfinder but only if you don't wear glasses and don't use a diopter lens screwed into the eye piece.

Even a diopter lens increases the tunel length limiting the users field of view through the viewfinder. The add-on Magnifiers, x1.25 & x1.4, increase the tunel even further.

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Thanks for explaining. I never thought about it being new to Leica Ms(new as in 1.5 years of using the M8 and no other Ms). I would look forward to a 0.85 or 1x VF

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Yes that is totally correct. You win the door prize.

Thank you for understanding. This forum seems to be a little short on that in this

thread.

 

Actually there is some room outside the 24mm framelines on the M8 viewfinder but only if you don't wear glasses and don't use a diopter lens screwed into the eye piece.

Even a diopter lens increases the tunel length limiting the users field of view through the viewfinder. The add-on Magnifiers, x1.25 & x1.4, increase the tunel even further.

 

I think its only temporary(i.e. the short of understanding) Most who responded are very helpful and I have appreciated their input in the past.

 

Sometimes I have foundations of assumptions that I have to readjust. That takes time.

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Again, explain why the M7 can have three different finder magnifications!

 

The incorrigible old man from he Age of Evidence

 

Compare the total field of view (the entire finder, not the framelines) of an M7 (0.72) and an M8 (0.68). I think - i no longer have a film M so can't check for myself - you will find that the M8 has both a lower magnification and a narrower total field of view.

 

Then explain why Leica should have chosen to do that if the thickness of the body didn't constrain them.

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Is there actually anyone that knows what the optical path looks like in a M viewfinder? Surely that is a key element in determining what is possible.

 

The magnification is nothing more than the relative angle of a incoming collimated beam compared to the angle of exit of a collimated beam, both with respect to the optical axis. There is nothing in there that neccesarily links the physical size, or the distance from the front to the back element, to the angle of acceptance. Take a microscope objective with NA=0.8, this allows light to enter and be imaged at sin(theta)=0.8 so about 106° field of view, nevertheless the front lens element is only about 1 mm diameter and the rear element (the ocular) is 160 mm away.

 

So I do not believe that the thickness of the body and the size of the front element (the rangefinder window) determines the possible magnification value and or the size of the visible frames. Which frames are visible depends only on the magnification and the angle of view that the eye can take in at a single glance.

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I don't know about the frame lines, but I have just checked a very reliable source, and apparently there are no expected delays on the M9 as at the time of writing.

M9 Current Delays

Edited by Nicoleica

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I don't know about the frame lines, but I have just checked a very reliable source, and apparently there are no expected delays on the M9 as at the time of writing.

M9 Current Delays

 

Hillaroius

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I do not believe that the thickness of the body and the size of the front element (the rangefinder window) determines the possible magnification value and or the size of the visible frames. Which frames are visible depends only on the magnification and the angle of view that the eye can take in at a single glance.

 

So if the body were three inches thick with a 1mm opening in the front, you have a plan for giving it a 21mm field of view? And .72x magnification as well? If the thickness of the body and the size of the window aren't factors, you claim it's possible....

 

The point is that there are MANY variables that contribute to the available FoV of a viewfinder. Body thickness (length of finder) is one of them. Change it (M8) and you have to change one or more of the others to compensate (32mm Fov 'sted 28, .68x mag 'sted .72x)

 

 

[EDIT: added M viewfinder pix - you're right they are hard to find on the Web]

-----

 

Nicole: Alas, the M8 is now showing a work delay - must be at Solms for servicing

Edited by adan

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Another solution is to make bigger front windows and increase the size of the internal components accordingly.

 

 

No cameras here with me to measure - but do I not recall that the main VF window on the M5 was larger, in part to provide backlighting for the metering scale on the bottom?

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