Shooting stars followup
The actual-pixels crop below from the Canon EF 35mm f/1.4L shows a strong aberration—a “bird’s wings” effect commonly known as sagittal coma flare. This looks like coma, but my reading of the definition of coma finds radial (sagittal) smearing. In this case, stars look like they have bird’s wings tangentially (the sagittal/radial streak is due to a 15-second exposure). While the NOCT-Nikkor (see yesterday) exhibits sagittal coma flare, the Canon EF 35mm f/1.4 exhibits a similar aberration tangentially.
Canon EOS 1D Mark III, EF 35mm f/1.4L @ f/1.4
The “bird’s wings” effect makes the lens troublesome for astrophotography; stars should be imaged as point sources, not smeared blobs. Stopping down to f/2.8 can largely eliminate the problem, but what is the point of owning an f/1.4 lens that must be stopped down to f/2.8? Even ignoring astrophotography, image quality is degraded with all subjects, smearing detail to an increasing degree away from the center of the image. The blur might be amenable to software correction, perhaps DXO Optics offers a solution.
The Zeiss ZF 35mm f/2 Distagon appears to offer excellent control of coma, imaging stars as point sources, but it is not perfect. Below is the worst case I could find, in the extreme corner on the EOS 1D Mark III, which appears to be a case of sagittal (radial) coma flare.
Canon EOS 1D Mark III, Zeiss 35mm f/2 ZF
I haven’t compared the Canon 35mm f/1.4L directly against the Zeiss 35mm at f/2, which would be the fairest test. However, daylight shooting suggests that the Zeiss 35mm offers superior correction of off-axis aberrations. A future writeup will explore these issues in detail.
