16-35 f4: Mostly likely cause of soft Left & Right Edges?

Started 3 months ago | Questions thread
Doppler9000 Regular Member • Posts: 311
Re: 16-35 f4: Mostly likely cause of soft Left & Right Edges?
3

nkistrup wrote:

Renting this lens for use on a Sony A7iii, converted to infrared. Using the Sigma MC-11 lens adapter.

After reading the user reviews on B&H Photo's site, numerous reviews on the Internet, and looking at images taken with lens on PixelPeeper.com, convinced that the softness issues on the right & left sides, but not the bottom, has to be due to one of the following:

  1. Infrared compatibility issue: Lens was designed for visible light use.
  2. Photographer is being a nitpicky jerk: Edge softness doesn't jump out while looking at the image on the screen ... only when I magnify to 100%. Saw some of this in the photos in PixelPeeper site, but not to the extent that I'm seeing it.
  3. Lens sample variation: Maybe I got a less than stellar copy from Lensrentals.com? Some reviewers mentioned that. This is my first experience w. a Canon lens. Have seen it w. Sony, Tamron, & Nikon, but not Zeiss or Voigtlander.
  4. Compositional Choices designed to find lens flaws: Most of the photos that I saw taken w. this lens on the PixelPeeper web site, didn't highlight bricks & similar objects at the edges. Many of may photos did.

All photos were taken raw, and converted using Capture One; tried DxO PhotoLab, and they came out worse. Tried with the Canon 16-35 f4 lens profile, as well as the generic one. And a tripod was used.

Here are the photos, full size & with EXIFINFO: https://graphitepaddle.smugmug.com/Infrared-photography/Lens-testing/Canon-16-35-f4/

Like this lens a lot. MF & AF work great. Focal length is a nice complement to my Tamron 28-75 f2.8. At the least, doing more testing this weekend. But wondering if I need to rent another copy, in case of copy variation?

Niels

The left and right sides of a 24 x 36 frame are significantly farther away from the center than are the top and bottom. If you look at MTF diagrams, you will see, in general, that as one moves away from the center, the image degrades at a higher than linear rate.

Wide zooms are probably the most challenging lenses to design, in terms of balancing the inevitable trade offs, as well.

Could this explain what you are seeing?

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