Mtf cam chat
The example below illustrates an MTF curve for a perfect* lens: Note: The spacing between black and white lines has been exaggerated to improve visibility.
MTF curve assumes a circular aperture; other aperture shapes will produce slightly different results.
The figure below compares a perfect lens to two real-world examples: Comparison between an ideal diffraction-limited lens (blue line) and real-world camera lenses.
The line pair illustration below the graph does not apply to the perfect lens.
To make things simple, we'll use images composed of alternating black and white lines ("line pairs").
Beyond the resolution of your lens, these lines are of course no longer distinguishable: Example of line pairs which are smaller than the resolution of a camera lens.
Move your mouse over each of the labels to see how high and low quality lenses often differ.
Alternatively, sometimes this frequency is instead expressed in terms of line widths (LW), where two LW's equals one LP.
No real-world lens is limited only by diffraction, although high-end camera lenses can get much closer to this limit than lower quality lenses.
Line pairs are often described in terms of their frequency: the number of lines which fit within a given unit length.
The highest line frequency that a lens can reproduce without losing more than 50% of the MTF ("MTF-50") is an important number, because it correlates well with our perception of sharpness.
A high-end lens with an MTF-50 of 50 LP/mm will appear far sharper than a lower quality lens with an MTF-50 of 20 LP/mm, for example (presuming that these are used on the same camera and at the same aperture; more on this later).
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