VRay Physical Camera Tutorial

If you haven’t used a manual photo camera in real life, this tutorial is for you!

As a photographer, I’ve always found the settings for VRay Physical Camera very natural and self-explanatory.
So it came as a bit of a surprise to find out how many people actually find them frustrating and hard to understand!

So here’s my attempt to simplify it a bit!

Focal Length

This is the first parameter you should pay attention to. It is set in millimeters and works just like changing a lens on a SLR camera.
Low value = large angle of view (Wide Angle lens in photographer lingo) High value = small angle of view (Tele Photo lens).
Just look at this image to see what I’m talking about!

Keep it realistic!

It is scientifically proven that the focal length of a human eye is ~45mm so images rendered with this value will look most natural to people. Wide angles will make rooms look larger, objects further away and distorted and stretched out. Tele photo lens (50mm+) will make objects appear closer to viewer and to each other as well as make spaces seem smaller.

SLR cameras use lenses from 6mm to 800, but most of the time it’s more like 16mm to 300mm. The extremely wide or tele lenses can cost as much as a nice used car, so most people don’t have a chance to buy them. This means that 99% of the photos you see everywhere are taken with a lens in 16-300mm range.
That’s why you want to stick to this range in your 3D renderings.

Sure, it might be fun to use very wide lenses, but it distorts the images quite a bit and should be used only when absolutely necessary.

So use your own discretion to choose a value, there are no hard rules here – use what works best for your particular image!

Framing your shot

Ok, so how do you actually frame the shot? I found that the most natural way for me is using the Walkthrough Mode.
So let’s say you’ve set the focal length to 24mm for an interior and now want to find a good shot.
The basic procedure is selecting your camera and pressing C to change your view to Camera. Once you’ve done that, turn on the Safe Frame to see exactly what will be rendered (Shit+F).
Now you are ready to move around – press the Up arrow key on your keyboard to enter the Walkthrough mode and click in the viewport. Now you can use the following controls to move around:

  • Up/Down – Move forward/backward
  • Left/Right – Move left/right
  • Left click + drag – look around
  • Middle click + drag – Pan up/down/left/right

If the camera moves too fast or too slow, use the bracket keys [ ] to adjust the walking speed!

It’s very similar to moving around in a video game and after a bit of practice you can get exactly where you want to be.

Vertical/Horizontal Shift

In real world architectural photographers use tilt/shift lenses or large format cameras with movable backs that rotate, and tilt to get these same results. But I don’t think it’s necessary to explain all that.
For us it’s very simple – 99% of the time all we want from this section is to get straight verticals in our image – just hit the Guess Vert button and be done with it. Vray will set the correct amount of Vertical Shift to straighten them out!


Horizontal distortion rarely look right, and it’s best to align the camera and target in a straight line manually if you need parallel horizontal lines.

Exposure (Brightness)

So this is the part that always get’s non-photographers confused.

“How do I make the image brighter? Do I change the Shutter Speed? Film Speed ISO? F/Number?
Which one is the correct way?”

The thing is… there is no CORRECT WAY! You have to use them together to get the correct result!

First let’s understand how the camera works!

Shutter speed controls how long the film or sensor is exposed to the light.
Long exposure means more light and brighter image, it also may cause fast moving objects to appear blurry – that’s Motion Blur.
Shutter speed is usually set in fractions of a second 1/200, 1/100, 1/30, etc. (in Vray Physical Camera the “1/” part is set by default so if you set the shutter speed to 50 it’s actually set to 1/50th of a second).

F/Number (Aperture) sets the diameter of the hole in the lens that let’s the light in. Larger opening let’s in more light and makes the image brighter, as well as increasing the DOF effect.
These numbers work in reverse so increasing the aperture value actually decreases the size of the hole! This means that f2 is brighter than f8 and f8 is brighter than f16 (you get the point!).

ISO just controls the sensitivity of the film/sensor. Higher sensitivity means brighter image, lower means darker image.
VRay artists are actually very lucky compared to real photographers – in real world increasing the ISO means increasing the image noise, so it’s limited in it’s use. For us however it doesn’t have this drawback!

You can increase (or decrase) this value as much as you want without any negative effects!

ISO is the most flexible way to adjust the exposure – it doesn’t affect anything else except the brightness of your render!

“Ok, but how do I set the exposure for my render?!”

Here’s a how you should do it – First decide if you will use camera DOF and Motion Blur (many people choose to add them only in post-production).
Adjust the F/Number to get the desired amount of DOF, adjust the Shutter Speed to get the desired amount of Motion Blur and finally use the ISO to get the desired Exposure of the image.

If you don’t want to use VRay DOF and Motion Blur – you can use any of these 3 parameters to get your desired exposure, it doesn’t matter and nobody cares which one you use! The result is still the same!

Vignetting

This parameter allows you to control the darkening of corners. I usually leave it at 1.0 and decrease only if I need very even light in the image. I think it helps to draw the viewer in and makes the image a bit more interesting.
Since it’s a natural phenomena that is present in real photos, I think it also makes the renders more realistic.
You can also turn it off by setting it to 0 and add vignetting in Post.

White Balance

Since all lights have a slightly different color, you can use this parameter to adjust the overall color tint of your render.
My advice is to set it to Neutral and forget about it – this way you can start without any color cast and mess with the colors later in Photoshop.

That’s it for today!
The rest of the settings are rarely used and perhaps I’ll explain them in future tutorials!

17 thoughts on “VRay Physical Camera Tutorial

  1. GREAT TUT FOR SUPPORT ME TO ACHIEVE GOOD QUALITY RENDERING…..
    THANK YOU SO MUCH..
    BUT WE WANT MORE KNOWLEDGE ABOUT VRAY…
    SO PLZ PROVIDE US…

  2. thank you.

    would an FNumber of .5 ever make sense? I have a camera outdoor scene far away. If I dont use a small F number the camera’s three grids dont space out correctly.

    • Even though in real life f 0.5 would be very uncommon/impossible, with vray there is no reason why you shouldn’t use it if the scene calls for it.
      So basically, sure, use any means necessary to achieve your shot.

  3. Thank you. Invaluable stuff!

  4. thank’s

  5. Thank you

  6. gracias, merci, shukran, Viscorbel

  7. for interior hall how we can use vray camera because i used vray light plane for celing also and when i go for AVI render animation walkthrough that time vray lights are shaking after i complete render can u give good procedure for walkthough with vraylight for celing with vray physical camera

  8. thanks a lot
    perfect information..

  9. Спасибо огромное за подробное описание! Только сейчас поняла последовательность установки настроек! Спасибо большое!

    – – – – – – – – – – –
    Thanks a lot for detailed explanation of the topic. I have just understood the step-by-step camera set ups! Thanks so much!

  10. Hi,

    Is it possible to adjust the dof of a camera whilst retaining the same exposure? For example doing various renders of the same object with different amounts of dof, but keeping their exposures the same? Maxwell does it really easily by automatically adjusting the shutter speed but I can’t see a similar way in vray? Any help would be much appreciated, thanks!

  11. I use Vray for sketch up…. and I can’t work out how to render in V ray the view I have in the sketchup window. I have tried various camera settings and its just not happening. Am I missing something?

  12. First, thanks for your tutorial. My question is what settings do you recommend for your render to appear more crisp and sharp?

    • A couple of things that can help:

      Change the AA filter to Mitchell-Netravalli or Catmull Rom
      Or turn it off altogether and use unsharp mask in photoshop.

      Turn up DMC sampler max subdivs 16~32 to get cleaner edges

      Reduce the Blur value of your DIFFUSE textures to 0.01~0.2

  13. good tutorial…..very helpful

  14. thanx for this awesome tutorial (Y)

  15. in the lens parameters for vray physical camera
    I can’t use the shutter speed do you know why ?

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