Just MTF Charts

Just MTF Charts: Nikon Prime Lenses

We’ll continue our just MTF chart series of posts with the Nikon brand prime lenses. For those of you who have been asking, The Digital Picture is going to add all our MTF graphs to their comparison tool as we release them. That will let you do logical comparisons like ‘is the Sony 135mm f/1.8 GM sharper at the edges than the Sigma 14mm f/1.8‘ to prove your brand is the absolute best in online forum wars.

Three quick answers to questions that I’m sure will be asked:

  • Z lenses testing requires sacrificing a camera and lens for electronics, machining a new mount for the bench, and wiring everything together. It’s a long and expensive process and we won’t have Z-lens test results for at least months. 
  • No, we don’t test stopped down. Lensrentals is willing to pay the cost for 10-copy tests wide open to establish standards for QA testing (which is always done wide open) and we share them. If you really want stop-down results, a 10 lens series costs $5,500. Email me and I’ll tell you where to send your check.  
  • The 24mm f1.8 isn’t missing because I forgot. I didn’t have enough results to post a 10-copy average.

 

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.

 

Nikon MTF Charts

Nikkor 20mm f/1.8G ED

Lensrentals.com, 2019

Nikkor 24mm f1.4 G ED

Lensrentals.com, 2019

Nikkor 28mm f1.8G

Lensrentals.com, 2019

 

Nikkor 28mm f1.4E ED (by special request)

We didn’t put this in originally because I didn’t have 10 copies to test. Here’s the results for 5 copies, it’s all I could get to.

Lensrentals.com, 2019

Nikkor 35mm f1.4G

Lensrentals.com, 2019

Nikkor 35mm f1.8G ED

Lensrentals.com, 2019

Nikkor 50mm f1.4G

Lensrentals.com, 2019

Nikkor 50mm f1.8G

Lensrentals.com, 2019

Nikkor 58mm f1.4G

Lensrentals.com, 2019

Nikkor 85mm f1.4G

Lensrentals.com, 2019

Nikkor 85mm f1.8G

Lensrentals.com, 2019

Nikkor 105mm f1.4E ED

Lensrentals.com, 2019

Nikkor 105mm f2.8G IF-ED VR Micro

Lensrentals.com, 2019

 

 

For a look at all the Just MTF Articles we’ve done so far, be sure to check them out here.

 

Roger Cicala, Aaron Closz, and Brandon Dube

Lensrentals.com

April, 2019

Addendum: The Digital Picture is hosting the MTF charts on their comparison tool, putting them up as we publish them here. It’s a great way to compare two lenses for the one or two of you who like to do that. The Canon and Zeiss primes are already up, the Sigma should be added by tomorrow.

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
  • Rokoko

    Thank you Roger!

  • bdbender4

    Ah, good to know, I also wondered about this.

    I also was curious about Nikon Z mount lenses, but am grateful for and not surprised at the explanation.

    As for the rest, it’s the same as it ever was. Thank you!

  • Ernest Green

    I assume all these tests are done wide open. Can/does a typical prime lens (or any lens for that matter) easily score at or above a “5” on the 50 line pair test when stopped down? Say to 2.8, F4, F5.6. In other words do all modern quality lenses perform similarly at 5.6 when it comes to the 50 line pair? I’d like to see just one example of a stopped down lens test.

  • P. Jasinski

    The kickstarter idea does not really sound that abstract. I would most definititely back that up, as this might spare many people a lot of trips to camera shops attempting to test their lenses on shop displays, small AF targets and random camera store items 😀

    If you count the time (or man-hours), I’d rather pay someone who actually knows what they’re doing 🙂
    A 100$? cound me in.

  • OK, I did the 5-copy run I was able to do and posted the results above.

  • Brandon Dube

    A million isn’t even a third of the funding it would take…

  • Brandon Dube

    No… MTF is just a thing. Whether lens A and B are the same model or different models is not relevant. If lens A and lens B differ at 20lp/mm by 0.1, one is going to look substantially better than the other.

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