New in Corona 10:
Easier workflow and greater creativity with control over channels affected by a Decal, cameras working inside volumes, improved DOF highlights, improved Caustics, fast and detailed Listers, and more.
Corona Decal "by channel"

The Corona Decal takes on a whole new life in your scenes, with the ability to have a Decal affect only particular channels in the material.
For example, you can now add a crack onto a brick wall, which you can easily move around and position, without disrupting the color and other parameters of the bricks and mortar. Or, as in the example below, add footprints using displacement that maintain the original texture for the ground.
Additionally, you can choose whether the Bump and Displacement channels in a Decal material either overwrite or combine with those channels in the base material.
Camera inside volumes

Freely place a Corona Camera anywhere in your scene, including inside volumes such as a Volume material, Phoenix simulations, or VolumeGrids for OpenVDB objects.
Now your cameras can fly through clouds and fog, rise and surface from below to above water, pass through fire, and more.

The Camera can also be given physical dimensions, useful when it is half-in and half-out of a volume, for example when half the image is underwater and half above the water.
Improved DOF blurring of highlights

Enabling the new DOF Highlight Solver will greatly improve the look of the blurring of any highlights (both reflections, and directly-viewed lights).

Better handling of your scenes with the new Listers

The Corona Lister now lets you view and adjust all the Lights (Lights, Light Materials, and Suns), Proxies, Displacement materials, and Cameras, in your scene (and in 3ds Max, also Displacement modifiers). In 3ds Max, the separate Scatter Lister has also been totally reworked, while in Cinema 4D the Scatter Lister has been added into the main Lister. This makes it much easier for you to find and adjust all these elements in your scene.

Brighter, more accurate Caustics

When rendering to large resolutions (4K or larger), Corona’s Caustics will now render brighter, and be more accurate and detailed.

Clouds affected by Sun Direct Color
If you choose to use the Direct Color for your Corona Sun, this will now affect the Procedural Clouds in the Corona Sky. For example, use a darker blueish color for a moonlight look, as shown below:
From this...

...to this (with some additional small tone mapping changes for exposure)

Or have a strong red for the Sun without it having to be low to the horizon - or choose more unusual colors such as green or purple for other-worldly looks, if that’s your thing!
Apply the same Triplanar, Color Correction, or Mapping Randomizer to multiple maps (3ds Max)

The Triplanar, Color Correction and Mapping Randomizer maps all now come with optional multiple inputs and outputs. Now you can apply the same settings to all the channels of one material from one place, rather than having to adjust three Triplanar nodes, or having to take the time to set up control nodes to control all the settings from one place.