Overview

The VRayPhysicalCamera uses real-world camera settings such as f-stop, focal

length, and shutter speed to set up the virtual CG camera. It also makes it easier to
use light sources with real-world illumination, such as VRayLight with physical units
or VRaySun and VRaySky.

UI Path: ||Create Menu|| > Cameras > V-Ray > VRayPhysicalCamera

||Create menu|| > Cameras > V-Ray > VRayPhysicalCamera

||V-Ray menu|| > Create > Cameras > V-Ray Physical Camera

Script Access

||V-Ray Toolbar|| > Physical Camera button

Image courtesy of Ken Vollmer

Basic & Display

Type – Specifies whether the camera has a target in the 3ds Max scene or not. This
helps to determinate the type of the camera. This mostly has an effect on the
motion blur effect produced by the camera.

Still cam – Simulates a still photo camera with a regular shutter.

Movie cam – Simulates a motion-picture camera with a circular shutter.
Video cam – Simulates a shutterless video camera with a CCD matrix.

Targeted – Shows the distance from the camera to the camera target,
when Targeted is enabled.

Focus distance – If enabled, specifies the distance at which objects are in focus.

Show cone/grid – Controls whether and when to show a preview of the camera field
of view and focus plane.

Selected – Only shows the preview when the camera is selected.

Always – Constantly enables the preview.
Never – Constantly disables the preview.
Cone only – Displays the cone in the viewport but removes the grid for the camera
view.

Show horizon line – When enabled, displays the camera horizon line in the viewport.
Example: Exposure, Field of View and Focus Distance

The focus distance of the physical camera (as specified by either the Target
distance or the Focus distance parameter) affects the exposure of the image and
the field of view for the camera, especially if the focus distance is close to the
camera. This is an effect that can be observed with real-world cameras as
demonstrated in the images below.

The set up is a white board with a small black rectangle and a camera in front of it.
Notice how changing the focus distance produces images with different brightness
even though the illumination and all other camera parameters are the same in both
cases. Also notice the change in the field of view.

The camera is focused on the white board; the grey color is approximately RGB 104,
104, 104.
The camera is focused at infinity; the grey color is approximately RGB 135, 135, 135.

Side view of the camera focused on the white board.

Side view of the camera focused at infinity.

Sensor & Lens

Field of view – When enabled, sets the field of view directly without having to set up
the Film gate and Focal length.

Film gate (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. Vertical film gate size is calculated by accounting image aspect ratio (vertical
film size = horizontal film size / aspect ratio).

Focal length (mm) – Specifies the equivalent focal length of the camera lens. This
setting takes into account the system units configuration to produce the correct
result.
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.

Example: Zoom Factor

This parameter determines the zooming (in and out) of the final image. It doesn't
move the camera forward nor backwards.

The following constant settings were used for some parameters: Exposure is set
to Physical Exposure mode, F-Number is 4.0, Shutter speed is 8.0, Film speed (ISO) is
100, Vignetting is on, White balance is white.
Zoom factor = 0.5

Aperture

Film speed (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 Film
Speed (ISO) example below.

F-Number – Determines the width of the camera aperture and, indirectly, exposure.
If the Exposure option is checked, changing the F-number will affect the image
brightness. For more information, see the F-number (s-top) example below.

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

Shutter angle (deg) – Specifies the shutter angle (in degrees) for the movie camera.

Shutter offset (deg) – Specifies the shutter offset (in degrees) for the movie camera.

Latency (s) – Specifies the CCD matrix latency (in seconds) when the camera mode
is set to Video cam.
Aperture F-number vs Shutter Speed vs ISO
Cheat Sheet

The main options that control the brightness of a V-Ray Physical camera are
Aperture F-number, Shutter Speed and ISO. They affect each other and you
need to balance their values according to your scene. Keep in mind that these
settings do not correspond to those of a real-life camera. They apply only to the V-
Ray Physical camera.

o F-number determines the size of the opening in the camera lens. The number
refers to the ratio between the aperture's focal length and the actual
diameter of the aperture. A smaller F-number means a larger aperture. The
larger the Aperture, the brighter the scene becomes but that also introduces
more Depth of field.

o Shutter Speed determines how long the lens stays open when taking the
photo. The numbers refer to fractions of a second. The slower the Shutter
Speed, the brighter the scene becomes but that also introduces Motion Blur.

o ISO determines the camera's sensitivity to light. Lowering the ISO means that
more light is needed to achieve good lighting. Increasing the ISO means that
less light is needed to achieve good lighting. A day scene, lit with a V-Ray
Sun, for instance, looks best when captured with around 100 ISO.
Example: Film Speed (ISO)

The Film speed (ISO) parameter determines the sensitivity of the film and
consequently the brightness of the image. If the ISO value is high (film is more
sensitive to light), the image is brighter. Lower ISO values mean that the film is less
sensitive and produces a darker image.

The images in this example show the effect of changing the Film speed (ISO). The
following constant settings were used for some parameters: Exposure is set
to Physical Exposure, Shutter speed is 8.0, F-Number is 4.0, Vignetting is on, and White
balance is white.
Film speed (ISO) is 50

Example: F-Number (f-stop)

Note: All the images from the following examples are rendered using
the VRaySun and VRaySky set with their default parameters.

The F-Number parameter controls the aperture size of the virtual camera. Lowering
the F-Number value increases the aperture size and so makes the image brighter
since more light enters the camera. In reverse, increasing the F-Number makes the
image darker, as the aperture is closed. This parameter also determines the amount
of the Depth of Field (DOF) effect. See the Depth of Field Example for more
information.

The images in this example show the effect of changing the F-Number. The following
constant settings were used for some parameters: Exposure is set to Physical
Exposure, Shutter speed is 8.0, Film speed (ISO) is 100, Vignetting is on, White
balance is white.
F-Number = 2.8

Example: Shutter speed

The Shutter speed parameter determines the exposure time for the virtual camera.
The longer this time is (small shutter speed values), the brighter the image would be.
In reverse - if the exposure time is shorter (high shutter speed value), the image
would get darker. This parameter also affects the motion blur effect, see the Motion
Blur Example.

The images in this example show the effect of changing the Shutter speed. The
following constant settings were used for some parameters: Exposure is set
to Physical Exposure, F-Number is 4.0, Film speed (ISO) is 100, Vignetting is on,
and White balance is white.
Shutter speed is 4.0

DoF & Motion blur

Depth of field – Enables the depth of field effect. Note that depth of field depends
on the Focus distance and F-Number parameters. For more details, see the Depth of
Field examples below.

Motion blur – Enables motion blur. Note that motion blur depends on how fast the
objects are moving, as well as the camera's Shutter settings. For more details, see
the Motion blur examples below.
Example: Depth of Field (DoF)

To enable the DoF effect you need to turn on the Depth of field option in the DoF &
Motion blur rollout of the physical camera. The effect is most strongly seen when the
camera is close to an object, for example when doing a macro photo. For a strong
DoF effect, the camera aperture must be open wide (i.e. small F-Number value).
That may lead to a very burnt and bright image, so to preserve the same illuminosity
over the whole image, the shutter speed must be shortened. And last but not least,
the Focus distance determines which part of the scene will be actually on focus. To
get the focus near, you would need a small value and reverse - higher value for far
focus.

For the images in this example, the following constant settings were used for some
parameters: Exposure is set to Exposure Value, F-Number is 1.0, EV is 7.0, Shutter
speed is 125, Vignetting is off.

Depth of field is off

Example: Motion blur (MB)

To enable the motion blur effect, you need to enable the Motion blur option in
the DoF & Motion blur rollout of the physical camera. The amount of motion blur is
determined by the speed of the moving object itself as well as the Shutter
speed setting of the camera. Long shutter speeds will produce more motion blur, as
the movement of the object is tracked over a longer time. In reverse, short shutter
speeds will produce less motion blur.

In this example, the falling roof tiles are moving faster than the flower pot, which
causes the difference in the motion blur effect.

For the images in this example, the following constant settings were used for some
parameters: Exposure is set to Exposure Value, EV is set to 7 and Vignetting is on.

Motion blur is off

Color & Exposure

Exposure – Specifies how the F-number, Shutter speed, and Film speed
(ISO) settings affect the image brightness. For more information, see Exposure, Field
of View and Focus Distance example above.
No Exposure – Shutter speed, F-number and ISO settings do not affect the image
brightness;
Physical Exposure – Image brightness is controlled by the Shutter speed, F-
number and ISO;
Exposure Value (EV) – Uses the Exposure value to control image brightness. Grays out
the ISO parameter and uses Shutter speed and F-number values only for Motion Blur
and Depth of field respectively.

Exposure value – Controls the exposure value when the Exposure Value (EV) option is
selected.

Vignetting – When enabled, simulates the optical vignetting effect of real-world

cameras. The strength of the vignetting effect can be specified, where 0.0 is no
vignetting and 1.0 is normal vignetting. For more information, see Vignetting
example below.

White balance – Allows additional modification of the image output. Objects in the
scene that have the specified color will appear white in the image. Note that only
the color hue is taken into consideration; the brightness of the color is ignored. There
are several presets that can be used, most notably the Daylight preset for exterior
scenes. For more information, see White Balance example below.

Custom balance – Specifies custom white balance.

Temperature (K) – Specifies the temperature (in Kelvins) when White balance is set
to Temperature.

The Exposure value option is connected to the F-number, Shutter speed, and ISO.
When Exposure Value (EV) mode is selected, changing the Exposure
value automatically shows the correct ISO value which is greyed out. When Physical
Exposure mode is selected, changing the value of ISO, F-number, or Shutter
speed automatically shows the corrected Exposure value which is greyed out.
Example: Vignetting

This parameter control the optical vignetting effect of real-world cameras.

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.
E.g. for daylight scenes this should be peach color to compensate for the color of
the sun light etc.

The images in this example show the effect of changing the White balance. The
following constant settings were used for some parameters: Exposure is set
to Physical Exposure, F-Number is 8.0, Shutter speed is 200.0, Film speed
(ISO) is 200.0, and Vignetting is off.

White balance is white (255, 255, 255)

Resolution Override

Override 3ds Max resolution – Enables resolution override for the

VRayPhysicalCamera.

Width – Specifies the override width for this camera (in pixels).

Height – Specifies the override height for this camera (in pixels).
Aspect ratio – Specifies the aspect ratio for this camera with an option to lock the
W/H values to the ratio.

X2 – Doubles the override resolution.

/2 – Halves the override resolution.

Swap W/H – Swaps the Width and Height values.

Auto update – When enabled, the 3ds Max resolution (specified in Render Setup >
Common tab) is updated when the camera is selected or any of the parameters
are changed.

Update – Updates the resolution only when this button is pressed. The Auto
update must be off.

Note that there will be improvements to the viewport updates with Resolution
overrides.

Tilt & Shift

Automatic vertical tilt – When enabled, preserves the vertical tilt when the camera is
being animated.

Vertical Tilt – Vertical tilt that allows the simulation of tilt lenses for 2-point perspective.

Horizontal tilt – Horizontal tilt that allows the simulation of tilt lenses for 2-point
perspective. Changing these parameters is similar to applying a camera correction
modifier.

Horizontal shift – Horizontally offsets the camera field of view as a fraction of the
current view. For example, a value of 0.5 will offset the camera one-half of the
current image width to the left.
Vertical shift – Vertically offsets the camera field of view as a fraction of the current
view. For example, a value of 0.5 will offset the camera one-half of the current
image height upwards.

Use the Guess vert tilt and Guess horiz tilt buttons to achieve 2-point perspective. For
more information, see the examples below.

Example: Vertical tilt

Using this parameter, you can achieve 2-point perspective. To have that done
automatically, use the Guess vert tilt button.
Vertical tilt = Guess (2 point)