This page provides information on the Physical camera attributes that are part of the V-Ray Camera Attributes.

 

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Overview


The VRayPhysicalCamera allows you to use real-world parameters to set up the virtual CG camera (e.g. f-stop, lens focal length etc). This gives you access to lens properties such as aperture (F-Stop) and shutter speed as well as depth of field, motion blur, and more.

V-Ray Physical Camera also makes it easier to use light sources with real-world illumination such as VRayLight with physical units, or VRaySun and VRaySky.

Choosing the Physical camera option for a camera node in Maya creates the Extra VRay Attributes as a rollout in the Attribute Editor for the camera.

 Adding the V-Ray Physical camera attribute will automatically enable the Treat as VRay Physical camera setting.

 


Image courtesy of Daniel Kho

 

UI Path



||Select camera||  > Attribute Editor >  Attributes menu > VRay > Physical camera


 

 

Physical Camera Attributes






Treat as VRay Physical camera –  Causes the standard Maya camera to act as a VRay Physical camera, and enables the remaining parameters in this rollout.

Type  – Determines the type of the physical camera to simulate. This mostly has an effect on the motion blur effect produced by the camera:

Still camera – Simulates a still photo camera with a regular shutter.
Cinematic camera  – Simulates a motion-picture camera with a circular shutter.
Video camera  – Simulates a shutter-less video camera with a CCD matrix. 

Film gate (in mm) – Specifies the horizontal size of the film gate in millimeters. Note that this setting takes into account the system units configuration to produce the correct result.

Focal length (in mm) – Specifies the equivalent focal length of the camera lens. This setting takes into account the system units configuration to produce the correct result. Vertical film gate size is calculated by taking image aspect ratio into account (vertical film size = horizontal film size / aspect ratio). This parameter is available only when Specify FOV is set to Off.

Specify FOV   – Specifies the source for the camera's field of view setting.

Off – The field of view is determined by the Focal length (in mm) parameter.
Specify – The FOV parameter becomes available for manual setting. 
From Maya camera – The field of view is determined by the settings of the Maya camera.  

FOV – A value for the camera's field of view when Specify FOV is set to Specify.

Zoom factor – Specifies a zoom factor. Values greater than 1.0 zoom into the image; values smaller than 1.0 zoom out. This is similar to a blow-up rendering of the image. For more information, see the Zoom Factor example below. 

  Distortion type  – Determines what formula is used to calculate the distortion for the camera

Quadratic – This is the default distortion type. It uses a simplified formula that is easier to calculate than the Cubic method.

Cubic – This is the distortion type used in some camera tracking programs like SynthEyes and Boujou. If you plan on using one of these programs, use this distortion type.
Lens file – An external .lens file is used to determine the distortion for the camera.
Texture – A displacement map from Nuke can be used to determine the camera distortion.

Distortion amount  – Specifies the distortion coefficient for the camera lens. A value of  0.0  means no distortion; positive values produce "barrel" distortion, while negative values produce "pillow" distortion. This parameter is available only when Quadratic or Cubic is selected as the Distortion type For more information, see the Distortion example below.

Lens file – The file used to calculate the camera distortion. This is only available when the Distortion type is set to  Lens file.

Distortion map – The texture used to determine the camera distortion. This is only available when the  Distortion type is set to Texture.

F-number Determines the width of the camera aperture. For more information, see the Exposure Control: F-Stop (f-number) example below.

Horizontal/Vertical lens shift  – Values other than 0 tilt the lenses to simulate 2-point perspective.

Guess vertical lens shift – Click to automatically set the Vertical lens shift parameter to achieve 2-point perspective. 

Shutter speed – The shutter speed, in inverse seconds, for the still photographic camera. For example, a shutter speed of 1/30 of a second corresponds to a value of 30 for this parameter. For more information, see the Exposure Control: Shutter Speed (s-1) example below.

Shutter angle – Shutter angle (in degrees) for the cinematic camera.

Shutter offset – Shutter offset (in degrees) for the cinematic camera.

Latency – CCD matrix latency, in seconds, for the video camera.

ISO – Determines the film power (i.e. sensitivity). Smaller values make the image darker, while larger values make it brighter. For more information, see the Exposure Control: Film Speed (ISO) example below.

Specify focus – This allows you to specify a focus distance different from the camera target distance.

Focus distance – Sets the focus distance of the camera.

Exposure color correction – When this option is enabled, the  F-number, Shutter speed and ISO settings affect the image brightness.

White balance – A color that can be used to alter the image output. Objects in the scene that have the specified color appear white in the image. Note that only the color hue is taken into consideration; the brightness of the color is ignored. For more information, see the White Balance example below.

Enable vignetting effect – When this option is enabled, the optical vignetting effect of real-world cameras is simulated. For more information, see the Vignetting example below.  

Vignetting amount – Specifies the amount of the vignetting effect, where 0.0 is no vignetting and 1.0  is normal vignetting.

Enable Bokeh effects – Defines the shape of the camera aperture. When this option is disabled, a perfectly circular aperture is simulated. When  enabled, a polygonal aperture is simulated. This option has an effect when depth-of field is enabled.

Number of blades – Specifies the number of blades of the polygonal aperture.

Blades rotation (in radians) – Defines the rotation of the blades.

Center bias – Defines a bias shape for the bokeh effects. Positive values make the outer edge of the bokeh effects brighter; negative values make the center of the effect brighter.

Bokeh anisotropy – Values other than 0 stretch the bokeh effect horizontally or vertically to simulate anamorphic lenses.

Enable Depth-of-field – Turns on depth of field sampling. For more information, see the Depth Of Field (DOF) example below.

Enable Motion blur – Turns on motion blur sampling. For more information, see the Motion Blur (MB) example below.  

Aperture map – Specifies a texture to define the shape of the aperture.

Affects exposure – When enabled, the size and shape of the aperture specified in the Aperture map affects the exposure of the final image.

Cat's eye bokeh – Controls the strength of the optical vignetting, also known as "cat's eye" vignetting. This effect is due to the fact that the shape of the bokeh highlights resembles the shape of the aperture. As the distance to the optical axis increases, the bokeh highlights are progressively narrowed and begin to resemble the shape of a cat's eye. The larger the distance from the image center, the narrower the cat's eye becomes. Optical vignetting tends to be stronger in wide angle lenses and large aperture lenses, but the effect can be noticed with most photographic lenses.

Rolling shutter mode  – Specifies whether the rolling shutter effect is enabled and the direction of the shutter. The Rolling Shutter effect options are active only if the Motion Blur is enabled. 

Disabled
Top to bottom
Bottom to top
Left to right
Right to left

Rolling shutter duration – The time for the shutter to pass through the image in 1/seconds.





Example: Zoom Factor


The Zoom factor parameter determines the level of zooming (in and out) of the final image. It does not move the camera forward or backward.


 

Settings for example images:

 

Exposure color correction: on
F-number:  8.0
Shutter Speed (s^-1):  60.0
ISO:  200.0
Enable vignetting effect:   on
White balance:   white

 


Zoom factor
: 1.0



Zoom factor
: 2.0



Zoom factor
: 0.5


 



Example: Distortion



Distortion:
1.0



Distortion:
-1.0




 

Example: Exposure Control: F-Stop (f-number)


Lowering the  F-number value will actually make the image brighter. Thus, the camera aperture is being opened, so more light is absorbed.

In reverse, increasing the  F-number will make the image darker, as the aperture is being closed. This parameter also determines the amount of the DOF effect.

Settings for example images:

Exposure color correction:   on
Shutter Speed:  150.0
ISO:   100
Enable vignetting effect:   on
White balance:   white
Lights: VRaySun and VRaySky with default parameters 


Note: The Sponza Atrium model was created by Marko Dabrovic (  http://www.rna.hr/ ) and was one of the models for the  CGTechniques Radiosity competition .



F-number:
8



F-number:
6



F-number:
4


 


 

Example: Exposure Control: Shutter Speed (s-1)


The Shutter Speed parameter determines the "exposure time", or how fast the shutter opens and closes. A lower value means the shutter is "slow", so the shutter is open longer, letting in more light and making the image brighter. Conversely, a high Shutter Speed means the shutter is open for less time, letting in less light and making the image darker.

This parameter also affects the Motion blur effect (see Example).

 

Settings for example images:

Exposure color correction:   on
F-number:  8.0
ISO:   200
Enable vignetting effect:   on
White balance:   white



shutter speed
: 200



shutter speed
: 100



shutter speed
: 400


 


 

Example: Exposure Control: Film Speed (ISO)


The ISO parameter determines the sensitivity of the virtual "film" in the camera. If the film speed (ISO) is high (more sensitive to light), the camera requires less light to get the image. Higher values are usually used for "night shot" images.


Settings for example images:

Exposure color correction: on
F-number:  8.0
Shutter Speed (s^-1):  400.0
Enable vignetting effect: on
White balance: white



ISO:
400



ISO:
800



ISO:
1600


 


 

Example: White Balance


Using the white balance color allows additional modification of the image output. Objects in the scene that have the specified color will appear white in the image. As an example, for daylight scenes the color can be set to peach to compensate for the color of sunlight.

Settings for example images:

 Exposure color correction:   on
Shutter Speed:  200.0
ISO:   200
Enable vignetting effect:   on
F-number:   8.0


White balance
- White (255,255,255)



White balance
- Blue (171,244,255)



White balance
- Peach (255,223,182)


 



Example: Vignetting



Vignetting:
Off



Vignetting:
On




 

Example: Depth Of Field (DOF)


To have the DOF effect you need to check On the Depth-of-field checkbox. Blades (Bokeh effect) is also part of the DOF effect.

The effect is strongly seen when the camera is very close to some object, just like doing a macro photo. So to have a strong DOF effect, the camera aperture has to be "open" - small F-stop value. That would lead to a very burnt/bright image, so to preserve the same illuminosity over the whole image, the shutter speed has to be quick. And at last but not least, the focus distance will determine which part of the field will be actually on focus. To get the focus near, you would need a small value and reverse - higher value for far focus.


 

Settings for example images:

Shutter Speed:  4000.0
ISO:   30
Enable vignetting effect:   on
F-number:   1.0

 


no DOF effect



DOF - On, focus distance: 80



DOF - on, focus distance: 140


 


 

Example: Motion Blur (MB)


In order for motion blur to appear in the rendering, the Enable Motion blur option must be checked.

The size/amount of the motion blur is determined by the speed of the moving object itself as well as the Shutter speed of the camera. Low shutter speeds will produce more motion blur, as the shutter is open longer and the camera sees the movement of the object longer in time. 

Keep in mind that lowering the shutter speed also brightens the image; to compensate for greater or lesser light due to changes to the Shutter speed, change the F-number value in the opposite direction (higher or lower).

 

Settings for example images:

 

Exposure color correction:   on
ISO:   8
Enable vignetting effect:   on



No motion blur



Motion blur enabled, F-number: 16.0, Shutter speed 4



Motion blur enabled, F-number: 8.0, Shutter Speed: 16


 

 


 

 

 Scripting

Add to node:

vray addAttributesFromGroup "perspShape" "vray_cameraPhysical" 1;

Attributes:

vrayCameraPhysicalOn
vrayCameraPhysicalType
vrayCameraOverrideFOV
vrayCameraPhysicalFilmWidth
vrayCameraPhysicalFocalLength
vrayCameraPhysicalSpecifyFOV
vrayCameraPhysicalFOV
vrayCameraPhysicalZoomFactor
vrayCameraPhysicalDistortionType
vrayCameraPhysicalDistortion
vrayCameraPhysicalLensFile
vrayCameraPhysicalDistortionMap
vrayCameraPhysicalFNumber
vrayCameraPhysicalHorizLensShift
vrayCameraPhysicalLensShift
vrayCameraPhysicalLensAutoVShift
vrayCameraPhysicalShutterSpeed
vrayCameraPhysicalShutterAngle
vrayCameraPhysicalShutterOffset
vrayCameraPhysicalLatency
vrayCameraPhysicalISO
vrayCameraPhysicalSpecifyFocus
vrayCameraPhysicalFocusDistance
vrayCameraPhysicalExposure
vrayCameraPhysicalWhiteBalance
vrayCameraPhysicalVignetting
vrayCameraPhysicalVignettingAmount
vrayCameraPhysicalBladesEnable
vrayCameraPhysicalBladesNum
vrayCameraPhysicalBladesRotation
vrayCameraPhysicalCenterBias
vrayCameraPhysicalAnisotropy
vrayCameraPhysicalUseDof
vrayCameraPhysicalUseMoBlur
vrayCameraPhysicalApertureMap
vrayCameraPhysicalApertureMapAffectsExposure
vrayCameraPhysicalOpticalVignetting