Just MTF Charts

Just the Cinema Lens MTF Charts: Canon and Sigma

We’re going to continue the Cinema prime MTFs with the Canon and Sigma lenses. Again, we’re not going in any particular order, other than what we have handy and what fits reasonably into a single post.

Since these are among our most popular cinema lenses, we do generally have at least a 10-copy set for each. The graph will tell you how many copies were tested for each lens.

A Quick How to on Reading MTF Charts

If you’re new here, you’ll see we have a scientific methodology to our approach, and use MTF charts to measure lens resolution and sharpness. All of our MTF charts test ten of the same lenses, and then we average out the results. MTF (or (or Modulation Transfer Function) Charts measure the optical potential of a lens by plotting the contrast and resolution of the lens from the center to the outer corners of the frame. An MTF chart has two axis, the y-axis (vertical) and the x-axis (horizontal).

The y-axis (vertical) measures how accurately the lens reproduces the object (sharpness), where 1.0 would be the theoretical “perfect lens”. The x-axis (horizontal) measures the distance from the center of a lens to the edges (measured in millimeters where 0mm represents the center, and 20mm represents the corner point). Generally, a lens has the greatest theoretical sharpness in the center, with the sharpness being reduced in the corners.

Tangential & Sagittal Lines

The graph then plots two sets of five different ranges. These sets are broken down into Tangential lines (solid lines on our graphs) and Sagittal (dotted lines on our graphs). Sagittal lines are a pattern where the lines are oriented parallel to a line through the center of the image. Tangential (or Meridonial)  lines are tested where the lines are aligned perpendicular to a line through the center of the image.

From there, the Sagittal and Tangential tests are done in 5 sets, started at 10 lines per millimeter (lp/mm), all the way up to 50 lines per millimeter (lp/mm). To put this in layman’s terms, the higher lp/mm measure how well the lens resolves fine detail. So, higher MTF is better than lower, and less separation of the sagittal and tangential lines are better than a lot of separation. Please keep in mind this is a simple introduction to MTF charts, for a more scientific explanation, feel free to read this article.

Canon CN-E

One thing I want to mention is the Canon CN-E MTFs for several lenses are different than the photo lens MTFs. This is not an error or a weird coincidence, it’s because they are not the same lens optically.

CN-E 14mm T3.1

Lensrentals.com, 2019

CN-E 20mm T1.5

Lensrentals.com, 2019

CN-E 24mm T1.5

Lensrentals.com, 2019

CN-E 35mm T1.5

Lensrentals.com, 2019

CN-E 50mm T1.3

Lensrentals.com, 2019

CN-E 85mm T1.3

Lensrentals.com, 2019

CN-E 135mm T2.2

Lensrentals.com, 2019

 

Sigma Cine FF

20mm T1.5 FF

Lensrentals.com, 2019

24mm T1.5 FF

Lensrentals.com, 2019

35mm T1.5 FF

Lensrentals.com, 2019

50mm T1.5 FF

Lensrentals.com, 2019

85mm T1.5 FF

Lensrentals.com, 2019

135mm T2.2 FF

Lensrentals.com, 2019

 

Roger Cicala, Aaron Closz and Brandon Dube

Lenrentals.com

May 2019

Author: Roger Cicala

I’m Roger and I am the founder of Lensrentals.com. Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

Posted in Just MTF Charts
  • Roger Cicala

    Alex, let me get the raw data out and look at that. It’s a setting error in the printout, but from outside the system I can’t tell if it compressed 20mm of data into 10, or just cut off at 10mm. I won’t be able to check for a day.

  • Alex Naanou

    Hi, is the CN-E 20mm T1.5 intentionally done to R=10mm? 🙂

  • Stanislaw Zolczynski

    Amazing quality of CN-20/1.5 comparing to Sigma.

  • Andreas Werle

    Hi Roger, thanks for showing us your data!
    I did compare the results of the Canon Cine lenses with the respective Charts of the EF-Lenses, they seem to be identical only the 135/2.2 is an exception. Is this one optically different? In case of the Sigma Cine-Lenses, the 35mm seems to be different. (Again both 24/1.4-1.5 show significant lower resolution.)
    Greetings Andy

  • Max Manzan

    Cool job.

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