Just MTF Charts

Just MTF Charts: Sony FE Mount Prime Lenses

This is the fourth post publishing all of our MTF results so that methodology is consistent and they are easy to find. The previous have been by lens brand. This one is by the mount, since the Zeiss Batis and Loxia lenses fit more naturally here than with the Zeiss SLR lenses. Otherwise, no comparisons, no commentary, just the test results for you to use and abuse as you see fit.

Oh, wait. One commentary. You’ll notice the Sony 28mm f/2 lens does not have 20mm results, it stops at 18mm. This lens has a small amount of copy-to-copy variation of distortion that makes the very edge results of our automated testing seem to have more variation than is real. Faced with the option of presenting questionable results or testing 10 copies by hand, I voted to just not present that data. I do want to emphasize this a technical testing issue, not something that would affect photography.

With that out of the way, here are the Sony FE mount prime lenses, followed by the Zeiss Batis and Loxia lenses. (The Sony 24mm f1.4 hasn’t been  tested yet simply because we can’t keep them in stock long enough to test them. I will add it when its testing is complete.)

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.

Sony FE Prime Lenses

Sony FE 28mm f/2

Lensrentals.com, 2019

Sony FE Sonnar 35mm f/2.8

Lensrentals.com, 2019

Sony FE Distagon T 35mm f1.4 ZA

Lensrentals.com, 2019

Sony FE Planar 50mm f1.4 ZA

Lensrentals.com, 2019

Sony FE 50mm f1.8

Lensrentals.com, 2019

Sony FE Sonnar T 55mm f1.8 ZA

Lensrentals.com, 2019

Sony FE 85mm F1.4 GM

Lensrentals.com, 2019

Sony FE 85mm f1.8

Lensrentals.com, 2019

Sony FE 90mm f/2.8 Macro G OSS

Lensrentals.com, 2019

Sony FE 135mm f/1.8 GM

Lensrentals.com, 2019

Zeiss FE-Mount Lenses

Batis

Batis 18mm f2.8

Lensrentals.com, 2019

Batis 25mm f2.0

Lensrentals.com, 2019

Batis 40mm f2

Lensrentals.com, 2019

Batis 85mm f1.8

Lensrentals.com, 2019

Batis 135mm f2.8

Lensrentals.com, 2019

Loxia

Loxia 21mm Distagon f2.8 

Lensrentals.com, 2019

Loxia 25mm f2.4

Note: this is data from only 3 copies. I have no excuses. I was lazy, the lens didn’t interest me much when it first came out, and I never went back and completed the testing.

Lensrentals.com, 2019

Loxia 35mm Biogon f2.0

Lensrentals.com, 2019

Loxia 50mm Planar f2.0

Lensrentals.com, 2019

Loxia 85mm Sonnar f2.4

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

March, 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
  • It takes a lot more glass to get a great 35mm. Consider: the Sigma 40mm f/1.4 is stupid huge and heavy. And while it’s nowhere near as sharp in the center as the Sony 135mm, according the LR’s mtf charts on the edge of the frame its actually sharper!

  • We’ve already tested almost all of them, you can usually find a post on the lens in question if you search. But yes, we’ll put up summary articles. They’ll be a bit longer since zooms have to be tested at multiple focal lengths, so they’ll come after the Cine primes.

  • Tae Kub

    Thanks you. Will you test the zoom lens?

  • Leo

    I don’t think anybody will simply put the manual lenses at infinity focus for testing because none of the manual lenses would be actually in focus at infinity. At least based on my experience, all MF lenses don’t have actual hard infinity stop because there’s way too many variables to control for.

  • CheshireCat

    You probably mean that the hard stop is slightly “beyond infinity”.

  • Max Manzan

    I’m sure Roger & co did focus the lens properly (likely for maximum contrast at 20 lp/mm, which is industry standard), but – indeed – if the lens was MTF-measured (and focused) with the focus ring positioned at the infinty hard stop, and I’d expect anybody to do so because it’s normal procedure, well this might have misplaced the floating element out of its optimum for infinity distance.

  • frankthp

    Many reports showed that the Loxia 21 (probably the whole Loxia series) has a hard stop at less than the infinity …perhaps it was taken account to the above tests?

  • In general, we can’t get 10 copies of the FE Voigts

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