Why do the M6 framelines shift?

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Hello all, can anyone tell me why this happens? When looking thru the m6 view finder and adjusting the focusing ring on my Summicron 50mm why does the framelines move, the movement is more prevalent when using the 50mm compared with the 35mm lenses. Is this something to do with the parralax correction?

Thanks in advance.

Richard

-- Richard Morgan (rmorgon@pps.com), January 01, 2002

Answers

Not "something to do with"--it IS the parallax correction at work.

-- Michael Darnton (mdarnton@hotmail.com), January 01, 2002.

Michael is right, this is parralax correction which is why the internal frame lines are nicer than uncoupled external finders. I think its ingenious!

-- Joel Matherson (joel_2000@hotmail.com), January 01, 2002.

If only they would change size like the old Konica S2, and show 100% instead of 80% of what's on the negative.

-- (bmitch@home.com), January 01, 2002.

Only 80%!!! This is disappointing; while I did not expect the 100% of the F3, 80% is not accurate enough for precise framing, especially if you do not intend to crop the negative. Is there anyway to compensate for this?

-- John Myers (mymacv@aol.com), January 01, 2002.

No easy way to compensate for this. The problem is that as you focus closer , the field of view for any given focal length gets larger. You can readily see this on an SLR. With a rangefinder, you have 2 choices. You can have the framing be 100% accurate at infinity, but then at 1 or 2 meters, you'd have much less on the film than in the frame (heads cut off, etc) Or you can have it be very accurate at the closer focusing range, but then at infinity you will get MORE on the negative than the frame shows. Leica chose the wiser second choice. There was talk of a sophisticated LCD frameline system that could take care of this. Maybe it will be implemented in 2015 in the M8 just as film becomes obsolete.

-- Andrew Schank (aschank@flash.net), January 01, 2002.


To say it covers only 80 percent may dramatize it a bit too much. 80 percent, I'm sure, refers to the area, not the height and width. If the finder covers 90% (0.9) of the height, and 0.9 of the width, appearing in the image, then 0.9 x 0.9 = 81% of the area. So you just "shoot loose" like going to the outside edges of the bright- lines for a shot at maybe 5 meters, and a bit beyond that, at infinity. Not too terrible.

-- Bob Fleischman (RFXMAIL@prodigy.net), January 01, 2002.

Thanks guys! Just checking that you really do know your stuff ;))

-- Richard (rmorgon@pps.com), January 01, 2002.

That's 80% of close-ups. For images taken at normal working distances it's much worse, maybe 65-70%. On a full-frame 8x12 inch print, probably an inch of the short side and an inch and a half of the long side are beyond what is outlined by the M6 viewfinder lines. M2, M3, & M4 are better, as are the LST cameras. Both the Imarect and older Universal finders show almost exactly 100% of the frame (as used by HC-B for his black border prints).

-- (bmitch@home.com), January 01, 2002.

"There was talk of a sophisticated LCD frameline system that could take care of this."

AKA the Contax G2 finder. 8^)

Actually I don't think the M finder is as low as 80. 85% or better is more like it. The 90 frames are the worst, because that lens shows more of a change over its range (shorter lenses change less, and the 135 doesn't focus as close) The 90 frames at 20 meters frame exactly like a 105 on a 100% Nikon viewfinder (15% error - or 85%). At 1 meter the 90 frames (talking M4-2 here) are so close to 100% that I have to be careful not to cut things off in the studio.

-- Andy Piper (apidens@denver.infi.net), January 02, 2002.


It doesn't require fancy LCDs to address this issue. Take a look at the Fuji GW670/690 series of medium format rangefinder cameras. Their viewfinder framelines not only shift, they expand and contract with lens focus changes. More than 90% accuracy is maintained under all conditions. Too bad Mamiya copied Leica and not Fuji when it designed its viewfinders for the 6 and 7.

-- Sal Santamaura (santamaura@earthlink.net), January 02, 2002.


My Fuji 645s has excellent an viewfinder that permits tight framing with a degree of precision. I suppose that this is easier to do with a fixed lens camera like the Fuji.

-- John Myers (mymacv@aol.com), January 02, 2002.

Three decades ago I owned a Rapid Omega, which had interchangable lenses, that also did the expand/contract/shift frame line trick. Must not be so hard.

-- Sal Santamaura (santamaura@earthlink.net), January 02, 2002.

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