diglloyd
diglloyd publication
Imagery: Auto - Large Table of Contents

Modulation Transfer Function (MTF)

The Sigma-supplied MTF chart indicates a lens with very good contrast wide open, indicating well-controlled aberrations. It’s not clear if MTF is computed or measured. Zeiss measures MTF and doesn’t ship a lens unless it meets specifications—computed MTF means that’s the best possible result, and real lenses might not perform as well.

The red lines are at 10 line pairs/mm and the green lines are at 30 line pairs/mm. The Sigma description states that the MTF chart is wide open (f/1.4), which is an outstanding MTF curve for an f/1.4 lens, and field shots do tend to confirm it. Compared to the Zeiss ZF 50/1.4 Planar MTF chart, the Sigma maintains notably higher contrast over much of the field at 10 lp/mm, a remarkable performance. Beyond that it’s hard to be sure; Sigma’s results may be computed (not measured) and are at 10/30 lp/mm vs 10/20/40 lp/mm for the Zeiss. Interpolating, fine detail MTF is probably a bit better with the Sigma at f/1.4.

Article continues for subscribers...

Already a subscriber? CLICK HERE TO LOG IN

Since 2006, Diglloyd Advanced Photography is the authoritative review and reference for DSLRs and their lenses: Canon and Nikon primarily, but also Pentax and some medium format. Reviews of key DSLRs are included, but the primary focus is on lens performance. Also included is a wealth of technique and workflow approaches.

DAP includes thousands of pages of exclusive coverage and high resolution Retina-grade examples detailing Canon and Nikon DSLR bodies and their lenses, with in-depth analysis of sharpness and contrast, color, bokeh, vignetting, distortion, MTF, and flare, behavioral and practical usage.

  1. Explore the table of contents
  2. View Lloyd’s Blog
  3. SUBSCRIBE NOW for $ per year.
Sigma 50/1.4 MTF, 10/30 lp/mm @ f/1.4

diglloyd Home Page | Terms of Use | PRIVACY POLICY | Contact
Copyright © 2008-2015 diglloyd Inc, all rights reserved.