This page offers information on Corona Camera in 3ds Max.
The Corona Camera can be used instead of the native 3ds Max cameras (Free, Target, Physical), and should be used instead of the obsolete CoronaCameraMod modifier.
It can be added from the Command Panel > Cameras > Standard menu, and it features all the photographic controls that can be found in a native 3ds Max Physical Camera, plus all the Corona-specific post-processing, panorama, VR, and other options.
The CoronaCameraMod modifier is still available in 3ds Max to guarantee backward compatibility for scenes saved with older versions of Corona. It should not be used in any other cases, though.
The Corona Camera can be created by going to Cameras > Standard. There is no separate Corona category (this saves you one click).
Corona Camera Settings
Targeted – Makes the Corona Camera targeted.
Horizon line – Enables/disables Horizon line.
Target distance – Defines the distance from the camera to the target.
Icon Size – The size of the camera origin icon in the viewport, relative to the default size (1.0).
Always – Always shows the camera cone.
Never – Never shows the camera cone.
When selected – Shows the camera cone only when camere is seleceted.
Sensor and lens
Field of view – Horizontal perspective FOV in degrees.
Focal l. mm – The distance between the lens and the image sensor when the subject is in focus.
Film width mm. – Affects the amount of the depth of field effect. Increasing this value increases the depth of field effect size. This is useful for matching other parameters and output to various real-world cameras. Typical values are 36mm for a full-frame digital SLR and 25.1mm for an APS-C digital SLR.
Zoom factor – Zooms in the view without changing the Filed of View or Focal Length. Higher zoom values result in a stronger Depth of Field. This is useful when matching real-world camera footage.
ISO – Affects image exposure when photographic exposure is turned on. Increasing this value increases exposure and vice versa. Standard values used in photography are: 50, 100, 200, 400, 800, 1600, 3200.
F-stop – Affects the depth of field effect and image exposure (when using photographic exposure). Decreasing this value increases the exposure and the depth of field effect amount, and vice versa. Standard values used in photography are: 0.7, 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32.
Shutter speed – Affects the image exposure (when using photographic exposure) and length of the motion blur effect. The input value is reciprocal to the result, so to set the shutter speed to 1/125 s, input 125. Longer exposure times increase exposure and motion blur length, and vice versa. Standard values used in photography are: 1, 1/2, 1/8, 1/15, 1/25, 1/30, 1/50, 1/60, 1/125, 1/150, 1/250, 1/500, 1/1000.
Shutter angle – A different way to express the shutter speed, using the movie camera convention of rotary disc shutter angle. The value is an angle out of 360-degree range, for which the shutter stays open. This means that for example, a value of 180 degrees means the shutter is open for half a frame (which is 1/50 s for 25 fps).
Mblur duration – A different way to express the shutter speed, using multiples of the current frame rate (fps). For example, a value of 0.5 means the shutter is open for half a frame (which is 1/50 s for 25 fps).
Shutter offset – Offsets the time interval from which the motion blur effect is generated. The value is defined in frames, with 0 meaning that the center of the interval is exactly in the current frame, -1 meaning that the entire interval happens just before the current frame, and 1 meaning the entire interval happens just after the current frame.
Enable include/exclude list – If enabled, only nodes specified by include/exclude list are visible when rendering using the selected camera.
DOF & Motion Blur
Depth of field can be easily toggled on and off from the Corona Camera’s UI, and the focus can be set by picking any object in the scene using the Override focus > Object option. The selected object’s pivot will be used to determine the position of the focus point. This is especially useful if the focus should be locked on a moving object during animation.
Camera – Enables the motion blur due to camera movements. For a complete motion blur solution, you need to enable geometry motion blur as well.
Geometry – Enables motion blur due to the movement of scene geometry. For a complete motion blur solution, you need to enable camera motion blur as well.
Shutter Curve – Allows to control Motion Blur by using a shutter curve.
Edit – Opens Corona Curve Editor.
For more information please check Camera Motion Blur Shutter Curve.
Depth of Field
Enable – Enables DOF effect.
Override focus – By default, the camera always focuses on its target distance. This override lets you specify another focusing method - either a distance separate from the target distance or focusing on another object pivot.
Value – Defines the focus target distance.
Object – Helper node, position of which specifies the focal plane of the camera. Useful to keep the camera focused on the given object.
Motion Blur Shutter Curve Examples
Override – Overrides the global Corona Render Settings related to DOF Bokeh with local camera values.
Circular – Sets the aperture shape that influences the out-of-focus blur called bokeh to the circular aperture.
Bladed – A polygonal aperture with a given number of sides (blades).
Blade count – Number of blades used for the DOF effect shape.
Rotation – Rotation offset of the DOF bokeh shape.
Custom – A custom aperture shape defined by a text map.
Affect exposure – The custom aperture may let through less or more light that a circular aperture. When this option is enabled, the exposure is adjusted accordingly; when disabled, the exposure stays unaffected by the aperture shape.
Center bias – Biases the lens transparent either towards the center or the edge of the aperture. Positive values created a ring effect; negative values create a sparkle effect.
Vignetting – Simulates the 'Cat eye' effect. typically prevalent on wide-angle lenses. Affects both the bokeh shape and the exposure (vignetting) near the image corners.
Anisotropy – Affects the aspects ration of the bokeh. If greater than 0, the bokeh is stretched horizontally, if lower than 0, the bokeh is stretched vertically.
Tilt & Shift
Automatic vertical tilt – Automatically sets the Vertical Tilt parameter to keep vertical lines straight and unaffected by perspective when the camera is looking up or down.
Projection & VR
Type – Projection type of the camera: orthographic, perspective, spherical 360°, cylindrical 360°, cube map 360°, fisheye.
Only perspective and orthographic projection can be accurately displayed in the viewport.
Vertical FOV [°] – Defines the degree of vertical field of view.
Ortho view size – Width of the orthogonal camera field of view in world units.
Ortho view in infinity – If set to true, the camera is considered to have originated in infinity. This means that all objects that fit in the camera's field of view will be visible no matter if they are behind or in front of the camera.
Field of view [°] – Field of view of the fisheye camera, captured by image circle.
Limit render to FOV – If true, all pixels outside of the selected field of view are rendered as black.
Projection – Specifies a projection of the fisheye camera:
Equidistant – Does not stretch objects in radial axis (along the line from image center to its edge). Most typical fisheye lens type.
Equi-solid angle – An object moving from the center of the camera to the edge gets distorted but maintains the same area in the renderer image.
Orthographic – Better preserves the center of the image at a cost of more distorting its edges. Typical door peephole lens.
Stereographic – Objects retain their general shape even near the edge of the image.
Cropping – Determines what part of the image circle is captured in the rendered image.
Virtual reality (stereo) – If enabled, two images (for left/right eyes) are rendered at the same time in the space of the selected render resolution. The resulting image can be loaded into the Samsung Gear VR or other virtual reality gadgets.
Eye separation – The distance between the left and right eye.
Eye front offset – The distance the eyes are shifted forward from the vertical axis rotation. There is usually no need to change this parameter.
Converge eyes – If on, the eye directions meet at some finite distance (as if they were looking at an object in that distance). If off, the eyes are perfectly parallel. The distance at which the eyes converge (where the center lines of their direction of view meet). This should be the average distance to walls in the scene. When in doubt, prefer larger values to smaller as they usually work better.
Starting with Corona 9, it is possible to Enable the Depth of Field in a Fisheye Camera. Simply create a Corona Camera, open the Projection & VR rollout, and set Type to Fisheye, then enable depth of field as usual from DOF and Motion Blur.
Cubic Account – Uses negative values to create a pincushion distortion (image center is ''zoomed out'') and positive values to create a barrel distortion (image center is ''zoomed in''). The default value of 0 produces no distortion.
Texture – Allows loading a map for distortion.
Environment & clipping
Enable – Enables camera clipping - only objects between the minimum and maximum distance are visible when looking through the camera both in the viewport and in rendering.
This applies just to direct visibility rays - it does not affect GI and reflections.
Show in viewport – Shows the clipping frame in the viewport.
Near – Only surfaces beyond this distance are visible through the camera.
Far – Only surfaces closer than this distance are visible through the camera
Show in viewport – Shows the environment range in the viewport.
Near/Far – Controls the eds Max Environment range. This is used for example by the 3ds Max native Fog effect and to set Z-Depth to render element range.
Camera physical size
Show in viewport – shows camera phisical size in viewport.
Size – Determines the physical size of the camera lenses. With the default value of 0, the camera will always either be competely inside a medium or competely outside of it. In order to render image which is partly in a medium and partly outside of it (e.g. an image that shows both above water and under water parts of the scene), you must set the physical size in such a way that a box of this size centered in the camera origin overlaps the boundary of the medium (e.g. the surface of the water). This imaginary box can also be seen as an objects with a slicer material that removes the part of the medium surrounding the camera.
To learn more about using the Camera Physical Size, see: New Volume Resolving in Corona 10 at the Chaos Help Center.
The following renders are from exactly the same scene. The volume is made from a simple water plane with displacement and surrounding walls.
The camera is below the water surface:
The camera is placed on the water surface:
- You can select both the Camera and its Target at the same time by clicking on the connecting line;
- You can see the Camera clipping planes in the viewport;
- You can easily resize the Camera’s viewport icon using the Icon size option under the Viewport display rollout;
- The camera's viewport icon changes according to the currently used VR mode (spherical, cylindrical, etc.);
Interactive Rendering - as opposed to the native cameras, Interactive Rendering will not restart when changing the tone mapping parameters of a Corona Camera.
Exposure, Tone Mapping, Post-processing
When rendering outside of the Corona Camera (e.g. from a free perspective view):
- The exposure, tone mapping, and post-processing settings available under Render Setup > Camera and inside the Post tab of the Corona VFB will be always used. These settings are locked to each other, so if you change a setting in the Render Setup dialog, the same value will be used in the VFB, and vice versa.
When rendering from a Corona Camera:
- If Use global exposure is selected under Photographic parameters of the Corona Camera - the image exposure is determined by the exposure settings available under Render Setup > Camera and inside the Post tab of the CoronaVFB.
- If Use simple is selected under the Photographic parameters of the Corona Camera - the image exposure is overridden by the Corona Camera. Exposure settings available under Render Setup > Camera and inside the Post tab of the CoronaVFB are ignored.
- If Use photographic (ISO) is selected under the Photographic parameters of the Corona Camera - the image exposure is overridden by the Corona Camera. Exposure settings available under Render Setup > Camera and inside the Post tab of the CoronaVFB are ignored.
- If any Override checkbox is enabled next to any of the settings inside the Corona Camera's Tone mapping and Postprocessing rollouts - those tone mapping and post-processing settings are overridden by the Corona Camera, and tone mapping and post-processing settings are available under Render Setup > Camera and inside the Post tab of the CoronaVFB are ignored.
The Override checkboxes specify whether the Corona Camera's or the global VFB/Render Setup settings should be used.
If the VFB Post tab is greyed out, it means that those settings are overridden by a Corona Camera or by the CoronaCameraMod modifier.
You will see a short note in the VFB explaining why it is so.
Saving and Loading Tone Mapping and Post-processing Settings
The Corona VFB offers Save and Load options, which can be used to save and load tone mapping and post-processing settings using the special CONF file format. Starting from Corona Renderer 4, those settings can be freely exchanged between the Corona VFB and the Corona Camera. This allows, for example, for:
- Defining the look of the image using the Post tab of the Corona VFB, and then moving those settings to a Corona Camera.
- Creating various post-processing presets, which can be then loaded into different Corona Cameras and the Corona VFB.
- Setting up multiple Corona Cameras with different post-processing settings, and then loading those settings from one of them into the VFB.
The Corona VFB's Post tab features various tone mapping and post-processing options, and the possibility to save and load them.
After clicking the Save button, you can save your custom preset as a CONF file.
You can then load the CONF file into a Corona Camera (and vice versa).
If the CONF file is loaded into the Corona Camera, and the Override checkboxes are enabled in that Corona Camera (to override the VFB settings), you will see that our custom post-processing preset is now used for the rendered image. So first we set up our desired post-processing in the VFB, then we saved them as a CONF file, and then loaded that CONF file into the Corona Camera.
If you render a non-camera view (in this case a free perspective view), only the settings available in the VFB Post tab are considered. Once you render from the Corona Camera again, the CONF settings loaded in that Corona Camera will be used again.