Just MTF Charts
Just the Cinema Lens MTF Charts: Xeen and Schneider
We’ve completed the MTF postings for all of the photo prime lenses. Now we’re going to start with the Cinema primes. For a lot of those that also have a photo version, the optics should be identical. That’s not always the case, however. Plus, the people interested in Cinema lenses aren’t usually the ones interested in photo lenses, so it’s worth posting the cinema version, if only to make them easier to find.
As I’ve mentioned before, we often don’t have 10 copies of the cinema version of a lens, so these are the average for whatever copies we were able to divert from rental long enough to test. The graph should show you how many copies were tested for each lens.
I’m not doing them in any particular order, just a couple of brands at a time. We’ll get to the others soon.
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.
Xeen Cinema Lenses
Just in case you are wondering, we test these in the different mounts and there is no MTF difference. If you weren’t wondering, carry on.
Schneider Cinema Lenses
Sorry, there are fewer copies here and not the complete set, but these are all I have.
The Cine-Xenar III series is designed for Super 35mm and crop sensor cameras, so they don’t cover the full 20mm off-axis.
Roger Cicala, Aaron Closz and Brandon Dube
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.