V-Ray Physical Camera Settings

[braddewald]

I began using the VrayPhysicalCamera about a month ago and feel like I am still adjusting the values for light arbitrarily. By this i mean the f-number, shutter speed (s^-1), and film speed (ISO). I can usually get an ok result but I feel, like I said, that I am choosing these numbers kind of arbitrarily. Are there any standard practices for setting up these numbers for interiors, exteriors?

I have been using (for interiors) an f-number of 8, a shutter speed of 35 and a film speed of 400. Any comments would very very much appreciated. I feel kind of lost.

[Kyle]

Try here:

 

http://www.spot3d.com/vray/help/150SP1/examples_vrayphysicalcamera.htm

[braddewald]

Thanks, Kyle, however I pretty much have spot3d as my homepage, lol. I understand what the values do, but I have no idea how much to tweak them. For instance, I could get a brighter image by just adjusting the f-stop, so why even mess with the shutter speed and film speed? Or vice-versa. Any suggestions?

[Kyle]

I'm not a master on the camera but I do know for interiors tend to use F-stop 4 exteriors start at around 8.

I was told that your shutter speed and film speed should be as close together as you can get them. I sometimes use 100 and 100 for this (working in linear workflow).

Not a full description but it's a start

[BrianKitts]

If you aren't playing with DOF or motion blur, then the values can be considered arbitrary.....it's when you start doing more advanced settings with you're camera that you need the different values.

 

for instance if you have moving objects in your scene you'll need to keep the shutter open longer to capture the motion blur.... which means adjusting your brightness with the Fstop or ISO.

 

if you are playing with depth of field, that's going to lock in which Fstop you use so then your exposure is controlled with the shutterspeed and ISO.

 

As for the ISO.... that one to me is still a bit arbitrary (if someone the wiser can give a better answer to this I'd appreciate hearing it) with your ISO, if you relate it to film speed in lower lighting conditions you need a higher ISO, problem in the realworld is that faster film typically causes more grain in the image. But in a render we don't have that problem because there is no grain generated by the higher ISOs. All the same I still set my ISO when rendering to what I'm finding works best with photography, 100 for exteriors, and 200 and up for interiors based on the darkness of the overall scene.

 

I'm just really starting to dive into real-world photography and it's really helping to build my understanding of the physical camera use in rendering.

Edited November 19, 2009 by BrianKitts

[braddewald]

I myself have condiered taking some kind of a short informal photography course to familiarize myself with its overarching principles but haven't gotten around to it. I guess this is the best thing I can hear, though: that I'm doing something right. Thanks, Brian.

[WAcky]

For me I set my ISO to 200 which is what my camera is set at for most of the time (to eliminate noise). Then I set my f-stop to a generic setting like 4 for indoors and 16 for sunny exteriors and I move my shutter speed from there. This means it's more likely to correspond with correct exposures that my camera would produce and means it's a bit closer to reality.

[Kyle]

For me I set my ISO to 200 which is what my camera is set at for most of the time (to eliminate noise).

 

Interesting how you up your ISO values to eliminate noise. Does this work?

[WAcky]

Well as mentioned above, the higher the iso, the more noise is introduced (AFAIK) so i just match my vray settings to my real-world camera settings.

 

(I think we may be confused about real world vs. vray)

 

The iso setting in vray will not affect noise.

[Kyle]

Your right I was confused then.

Thanks for clearing that up.

[Nic H]

Yep like Brian said unless you need to do DOF and motion blur in camera you can just set the ISO and shutter speed to the same value - any value, which basically locks them (for want of a better word) leaving you to expose using only the F number.

 

Its very easy this way, then if you need to add motion blur in camera just adjust both values down to something like 25-50 and tick motion blur and render.