How to Read a Lens MTF Chart

In this video by the California based photo store Linco, you will learn how to read what is known as a lens  MTF (or Modulation Transfer Function) chart. This chart – released by many lens manufacturers on their websites along with their lenses can give you a basic understanding of how much detail the lens can resolve across its entire range – from the center to its edges.

Do keep in mind a few things:

  1. MTF charts are released by the manufacturer and not and external unbiased 3’rd party – consider them as that.
  2. Do not compare MTF charts of one manufacturer to another – each manufacturer has its own methodology for making charts. We should also not advice you to compare on type of lens to another (prime lens to zoom lens charts and even very different focal lengths are not necessarily good candidates for comparison).
  3. When referring to a full frame lens always keep in mind that if you are not using a full frame camera you should not consider the entire chart but just the horizontal axis relevant for the smaller sensor (typically around 15 on the horizontal axis and not beyond).
  4. Finally, in this video we are shown a Canon MTF – keep in mind that other manufacturers do not always provide the data for the closed aperture (so each lens is only shown on the graph as wide open). See for example Nikon’s take on how to read MTF charts.

2 comments

  1. Your third paragraph in that “Keep In Mind” list clearly suggests, that using a Full-Frame lens on an APS-C camera is the best choice to make, having got rid of that otherwise “inevitable” performance falloff

  2. Its a complicated subject. On the one hand, yes – the center of a FF lens should produce the best IQ and when put on a crop sensor this is basically what you get. On the other hand good crop lenses are designed for crop bodies so its not necessarily that they will preform significantly worse – and of course at any case you loose the advantages of the FF sensor which could be more significant then the little extra IQ you gain.

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