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Rolleinar 2.8/35mm MTF
I found this chart after purchasing the lens, in a Voigtlander forum! Seems the Rolleinar 2.8/35 is the same lens as the Voigtlander Color-Skopal 2.8/35, both made by Mamiya in Japan. For anyone unfamiliar, Mamiya lenses are legendary.
Actual shots confirm the MTF charts: except in real life, my lens appears to render IQ better than the charts would indicate. The charts above are for the very early lenses: mine is a later, improved, Japan version. Overall, the lens compares favourably with today's f2/8/35mm lenses, and provides excellent contrast and resolution.
How to read an MTF chart?
[MTF= Modulation Transfer Function]
[lppmm= line pairs per millimetre]
* The chart displays 2 lines for different lppmm at different f stops.
* The solid lines measure 'sagital lines", running diagonally from lens left bottom corner, through centre, to right top corner.
* The dotted lines measure "meridonial lines", running perpendicular to sagital.
* The solid and dotted lines are grouped in pairs and displayed for 10, 20, 40 lppmm.
10 lppmm relates to contrast.
40 lppmm relates to resolution.
* In general: the higher the curves show on the chart, the better; the flatter the curves, the better; the closer the solid and dotted lines are to each other, the better.
* The number on the X axis is the diagonal distance from lens centre. Thus, 10 indicates a 20mm circle diameter imposed upon the centre of the 36x24 frame, for about 50% coverage overall.
* Due to inherent limitations of glass and design, lenses are optimised at a specific aperture, usually f8 for legacy. Thus, most charts show the curves progressing flatter as the lens is stopped own.
* Many factors determine the overall performance of a lens, more than MTF can measure. MTF serves objectively as a starting point.
Is contrast more important than resolution for general photography? Yes. Sharpness. Our eyes perceive sharpness as a function of contrast between items photographed: example, foreground against background..
Is resolution important? Yes. Without resolution, fine details are not visible. But how much is enough or too much? This answer depends entirely upon the photographer. Portraits require 'pleasing' resolution, and most top lenses provide more than enough to show clearly facial wrinkles and blemishes. Spy satellites require ultra resolution, and never have enough.
Rolleinar 2.8/35mm MTF
I found this chart after purchasing the lens, in a Voigtlander forum! Seems the Rolleinar 2.8/35 is the same lens as the Voigtlander Color-Skopal 2.8/35, both made by Mamiya in Japan. For anyone unfamiliar, Mamiya lenses are legendary.
Actual shots confirm the MTF charts: except in real life, my lens appears to render IQ better than the charts would indicate. The charts above are for the very early lenses: mine is a later, improved, Japan version. Overall, the lens compares favourably with today's f2/8/35mm lenses, and provides excellent contrast and resolution.
How to read an MTF chart?
[MTF= Modulation Transfer Function]
[lppmm= line pairs per millimetre]
* The chart displays 2 lines for different lppmm at different f stops.
* The solid lines measure 'sagital lines", running diagonally from lens left bottom corner, through centre, to right top corner.
* The dotted lines measure "meridonial lines", running perpendicular to sagital.
* The solid and dotted lines are grouped in pairs and displayed for 10, 20, 40 lppmm.
10 lppmm relates to contrast.
40 lppmm relates to resolution.
* In general: the higher the curves show on the chart, the better; the flatter the curves, the better; the closer the solid and dotted lines are to each other, the better.
* The number on the X axis is the diagonal distance from lens centre. Thus, 10 indicates a 20mm circle diameter imposed upon the centre of the 36x24 frame, for about 50% coverage overall.
* Due to inherent limitations of glass and design, lenses are optimised at a specific aperture, usually f8 for legacy. Thus, most charts show the curves progressing flatter as the lens is stopped own.
* Many factors determine the overall performance of a lens, more than MTF can measure. MTF serves objectively as a starting point.
Is contrast more important than resolution for general photography? Yes. Sharpness. Our eyes perceive sharpness as a function of contrast between items photographed: example, foreground against background..
Is resolution important? Yes. Without resolution, fine details are not visible. But how much is enough or too much? This answer depends entirely upon the photographer. Portraits require 'pleasing' resolution, and most top lenses provide more than enough to show clearly facial wrinkles and blemishes. Spy satellites require ultra resolution, and never have enough.