VRayPhysicalCamera examples

Thứ Ba, 2 tháng 8, 2011

















Search Keywords: camera, physical camera, exposure, f-stop, shutter speed, iso, vignetting, dof, motion blur, sun , sky, 2-point perspective





Note: the Sponza Atrium model is created by Marko Dabrovic (http://www.rna.hr ) and is one of the models for the CGTechniques Radiosity competition . The Athene model is a free model from the DeEspona Infografica model bank .





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



Example 1: exposure control - f-number (f-stop)




This 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 DOF effect, see Example 9.





Exposure is onShutter speed is 60.0ISO is 200Vignetting is onWhite balance is white










f-number is 8.0


f-number is 6.0


f-number is 4.0




Example 2: exposure control - Shutter speed




This parameter determines the exposure time for the virtual camera. The longer this time is (small Shutter speedvalue), the brighter the image would be. In reverese - if the exposure time is shorter (high Shutter speed value), the image would get darker. This parameter also affects the motion blur effect, see Example 10.





Exposure is onf-number is 8.0ISO is 200Vignetting is onWhite balance is white.










Shutter speed is 60.0


Shutter speed is 30.0


Shutter speed is 125.0




Example 3: Exposure control: film speed (ISO )




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





Exposure is onShutter Speed is 60.0f-number is 8.0Vignetting is onWhite balance is white.








ISO is 400


ISO is 800


ISO is 1600




Example 4: Zoom factor




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





Exposure is onf-number is 8.0, Shutter speed is 60.0ISO is 200.0, Vignetting is onWhite balance iswhite










Zoom factor is 1.0


Zoom factor is 2.0


Zoom factor is 0.5




Example 5: Vertical shift (Camera Correction)




Using this parameter you can archive the so called "2 point perspective". To have that done automatically, use the Guess vertical shift button.










vertical shift: Guess (2 point)


vertical shift: -0.5


vertical shift: 0.5




Example 6: Distortion




The difference between the two types of distortion is slightly visible. The Cubic type should be used in some camera tracking programs like SynthEyesBoujou etc.










Distortion is 1.0Distortion type is Quadratic


Distortion is -1.0Distortion type is Quadratic


Distortion is 1.0Distortion type is Cubic


Distortion is -1.0Distortion type is Cubic




Example 7: Vignetting




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








Vignetting is 0.0 (vignetting is disabled)


Vignetting is 1.0




Example 8: 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.





Exposure is onf-number is 8.0, Shutter speed is 200.0ISO is 200.0, Vignetting is on








White balance is white (255,255,255)


White balance is blueish (145,65,255)


White balance is peach (20,55,245)




Example 9: Depth Of Field (DOF)




To enable the DOF effect you need to turn on the Depth-of-field option in the Sampling rollout of the physical camera. The effect is most strongly seen when the camera is close to some object, like 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 shortened. And at last but not at 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. 





Exposure is onf-number is 1.0, Shutter speed is 4000.0ISO is 200.0, Vignetting is on








DOF is off


DOF is onFocus distance is 400


DOF is onFocus distance is 4000




Example 10: Motion Blur (MB)




To enable the motion blur effect you need to turn on the Motion blur checkbox in the Sampling rollout of the physical camera. The amount of the 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 in time. In reverse, short shutter speeds will produce less motion blur effect. Keep in mind that to preserve the same illuminosity over the whole image, the f-number value has to be corrected as well.





Note that in the example the far object is moving quicker than the near one, which cases the difference in the motion blur effects.





Exposure is onISO is 200.0, Vignetting is on










Motion blur is off


Motion blur is onf-number is 16.0Shutter speed is 30.0


Motion blur is onf-number is 8.0Shutter speed is 125.0



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