What are the Differences between the Canon RF 85mm F1.2 L USM and USM DS Lens?

With the Canon RF 85mm F1.2 L USM Lens announced and coming soon and the similarly-purposed Canon RF 85mm F1.2 L USM DS Lens not being slated for delivery until the second half of the year, some need to make a buy or wait decision. In his usual clear and accurate style, Canon USA's Rudy Winston has explained the differences between these two lenses.

What are the differences between the Canon RF 85mm F1.2 L USM Lens and the Canon RF 85mm F1.2 L USM DS Lens?

Per Rudy:

• Reduced light transmittance:
  The Defocus Smoothing coatings in the 85mm F1.2 L DS lens will reduce actual light transmission by up to 1.5 stops, when the lens is at its widest aperture.
• Defocus Smoothing effect is aperture-dependent:
  The visual impact of softer-edged, out-of-focus highlights, is at its maximum when the DS lens is shot wide-open. The visual impact of Defocus Smoothing diminishes, vs. the RF 85mm F1.2 L lens, as the DS lens’ aperture is stopped-down, and essentially disappears if the lens is stopped-down several stops from wide-open.
• Depth-of-field is rendered differently:
  At wider lens apertures where the Defocus Smoothing effect is visible, for technical reasons, depth-of-field will appear deeper in shots taken with the DS lens, vs. identical shots taken with the RF 85mm F1.2 L USM lens.

Rudy provides additional information worth reading, but click on the two sample images that are shared in the article for comparison purposes. They should open in new tabs. Then click back and forth between the two tabs while observing changes.

The first observation to make is that the DS lens produces much smoother blurred lights in the background and this is the key advantage of this lens. While looking at those lights, you will likely notice that the non-DS lens' sample image has larger-sized blurred lights. However, the size difference may not be related to the non-DS vs. DS designs. Next notice the sharpness of the model's shoulders in the two images. That the front shoulder is sharper in the non-DS lens image and that the reverse is also true may indicate that the non-DS lens was focused to a closer distance, causing the blurred lights to be larger on this account.

Portrait photographers are going to love these lenses and Rudy's "Which lens is right for you?" section should be helpful to those selecting between the two.