Real Camera Simulation Using VRayPhysicalCamera

[heshamelshipli]

Hello everybody.

 

I am trying to simulate a real photo using 3DS Max and V-Ray

I am using VRayPhysicalCamera

 

I use meta data also called EXIF of the original photo

Here is example of the EXIF :

I always read that VRayPhysicalCamera simulates the real camera.

But as you see there are some different parameters not included in V-ray Camera

So What I need to understand,

What is the meaning of "35mm focal length Value 90"

So focal length is 35 or 90 ?!!

Also how can I simulate "Max Aperture" in Vray Camera ?

You can see "No Flash"

Is there any way to simulate flash on/off in Vray Camera ?

Also there are settings I don't know what is the importance of them

in VRayPhysicalCamera .. You can see here :

fov and zoom factor and specify focus .

I never touch these parameters and every thing is ok

I would appreciate if any pro here clarified these parameters for me/us

[zhopudey]

Well, the 5dmk3 is a full frame camera. So set your vray camera film gate to 36mm. Focal length to 30mm, zoom factor to 1.

[Chris MacDonald]

What is the meaning of "35mm focal length Value 90"

So focal length is 35 or 90 ?!!

Also how can I simulate "Max Aperture" in Vray Camera ?

You can see "No Flash"

Is there any way to simulate flash on/off in Vray Camera ?

Also there are settings I don't know what is the importance of them

in VRayPhysicalCamera .. You can see here :

[ATTACH=CONFIG]52067[/ATTACH]

fov and zoom factor and specify focus .

I never touch these parameters and every thing is ok

I would appreciate if any pro here clarified these parameters for me/us

 

35mm is talking about the size of the sensor on the camera. The 5D is a full frame camera as the post above said.

 

The reason for this is that some cameras have a smaller sensor (APS-C, etc) and thus you need to apply a crop factor.

 

The aperture is the f-number.

 

As for the flash on/off... The Vray cam doesn't have a flash, but you could simply attach a light 30mm or so above the camera to simulate a flash.

[Corey Beaulieu]

FOV = Field of View. It refers to the angle that the camera can see from right to left. It is defined by the MM of the lens, but some cases may require that a FOV value be used instead of a lens value. Not necessarily for matching a real world camera, but CG has a lot of different applications.

 

Zoom Factor = Crop Value. Most generally put, if you are using another sensor type as the other posts have mentioned, one like the Nikon D90, the sensor is cropped and a lens value recorded at 24mm in the Meta Data is actually the viewing angle of a 36mm lens. You would correct this by applying a Zoom Factor of 1.5 in the Vray Camera.

 

Specify Focus = A Depth of Field parameter. In a real world camera, the user picks an object and sets the focus of the camera to that object. depending on the image being captured, this places other objects out of focus. Vray uses this value and a DOF sampling to help simulate this effect. You need to tick on DOF in order for it to work and the render time is going to go up significantly.

 

Max Aperture is a specification of the camera/lens you are using and not a value to be simulated. It is just a fact about the lens. Your Aperture is your F-Stop as Macker pointed out and that value is 3.5.

 

Lastly, if you are aiming to simulate a real world camera, it would be wise to turn off vignetting. This effect applies an over-darkening effect to your image and will not appropriately match the brightness.

[heshamelshipli]

Thank you guys, Really appreciate.

Here you can find the camera in 3ds max viewport

 

 

And here is the EXIF Of the true image I am working on

 

 

I put all the parameters like the EXIF here :

 

 

When I put film gate 36mm the scene gets distorted as shown in the first image above.

but I got all details in the original photo here :

 

 

When I put film gate 20mm and move the camera backward distortion is gone but

I lose a lot of details and vanishing point changes like here :

 

 

The original photo is slightly distorted but not like mine

you can notice that in this crop :

 

 

So how to remove distortion without losing details and keeping my vanishing point ?

Where to place V-ray camera in the scene exactly ?

Sorry for asking too much but it is my first time to simulate a real photo.

Waiting for your comments.

Thank you.

[heshamelshipli]

I already made a reply to this post but it wasn't published !!

I will make it again

 

Thank you guys, I really appreciate these great comments.

Here I will post both the original photo I am working on and

the one in my viewport to clarify the problem with me.

 

Here you can see the original photo :

 

When I make Film Gate = 36mm

I got my camera view like this :

 

 

You can notice distortion in the camera view.

But all details and vanishing point are almost correct.

 

But when I make Film Gate = 20 and take the camera away from the scene

There is no distortion but I lose a lot of details and vanishing point also.

You can notice that here :

 

Original photo EXIF here :

 

 

My V-Ray Camera settings here :

 

 

The original photo has a little bit distortion but not like my viewport

You can notice that here in this crop :

 

 

So, What is the solution for this ?

Where to put my camera in the scene ?

Waiting for your comments and I wish that my comment is published !!

[Corey Beaulieu]

Your film gate should be set to 35mm not 20. And with a zoom lens, the 30mm focal length recorded is not exactly correct. You will be within that area, but not exact.

 

If you are going to photo match something, you need to be sure and place a camera in the 3D the same rough dimensions as they were in reality. then you will line up your verticals and match the dimensions of the space. The camera settings are only one part of the equation.

[heshamelshipli]

Thank you Corey.

But a lot of 3D artists make 3d scenes using camera match without knowing the correct place of the camera

in the real picture and that is my last question

How to make it properly ? without any kind of distortion ?

I hope anybody can help us here.