How DOF and Physical Camera works??

[orei]

Hi my friends.. i'm an italian user.. i haven't understood how DOF work.. i've tried with the tutorial and the scene for vray.. in the tutorial.. the misure are in architectonical inches format. but.. if i use decimal meter format.. the value that i insert in the option panel for DOF.. are used in meters, or in inches format??

There is any interactive tutorial for those parametrer??

An other information.. i've already read the whole manual about VfSU.. and i think.. that i need more and more information.. that in this manual.. are not explaned.. where can i found a very good manual or tutorial?

Thanks a lot

[thomthom]

Re: How DOF and Physical Camera works??

The DOF always take the units in inch. I agree that the manual and/or the DOF setting section should specify this clearly. It confused me to begin with as well as I expected it to use the scene units, which I always keep in mm.
Or they could implement a drop down next to the value where you choose what units type you want to specify the DOF in.

[orei]

Re: How DOF and Physical Camera works??

so i need to convert my misure in inches format??

but.. if i've the template in meter.. i use the vale in inches?and if are in cm or mm? always in inches? what a pity that they haven't implemented a menu to select ather format! Hope in the next release.. in case.. i use a unit converter.

For he other question.. for any manual?? thanks a lot

[thomthom]

Re: How DOF and Physical Camera works??

Yes, the VfSU dialog DOF always use inches. So when you have your focal distance convert it into inches and you'll be all set.

[dalomar_cg]

Re: How DOF and Physical Camera works??

How exactly are you using DOF...with the regular camera or with the physical camera? With the physical camera, its very simple as it takes the Fstop value and references that (along with the focal length) to figure out the exact DOF. With the regular camera, you're not so lucky. The Aperture value is specifying the exact size of the camera opening that will determine depth of field. The larger the size, the shallower the focus (ie. more blurring). This value is in scene units, so you have to be aware of that.

Most people are used to determining the amount of DOF with the Fstop number. There is a correlation between Fstop and aperture size, but its a slightly convoluted equation, since it involves the focal length (which you'd have to compute from FOV b/c thats what SU uses) and a possible unit conversion as the formula itself returns the aperture size in mm.

If you're using the standard camera, and don't want to go through all the hassle for the aperture value, you can always just switch to the physical camera and disable exposure. That will allow you to set DOF using the Fstop.

[thomthom]

Re: How DOF and Physical Camera works??

I've only used the Physical Camera and Override Focal Length. And the Override Focal Length only takes inches.

[dalomar_cg]

Re: How DOF and Physical Camera works??

Focal length is in millimeters not inches...Think of focal length as the Zoom on a camera.

[orei]

Re: How DOF and Physical Camera works??

so.. uhm.. how many trouble.. :P

I understood now.. why the render comes very different from my visualization..

I use the physical camera.. because without it.. the image is burn.. i've already drop down the iso.. and set the aperture.. but i'm not able to do a good render.. for a correct information.. i'm a very very prary render user.. so.. i'm a noooooooob!!

But i'm lurning.. because.. is wonderful do a render.. and see what the light can do over my models!!!

But.. the vray manual.. is very limitate.. sighh..

So.. to do a correct render with depth of field.. need to use physical camera really? ok..

Type: still camera

Shutter speed: 150 (is the number that in the formule 1/x gave me the time for the aperture.. wright?)

Override focal lenght: if it's check.. what really do? the focal lenght.. i've understood by many try, that is the distance between the camera and "where" i see the image.. so.. if i type 200, i see the image 20cm far from where i'm with the screen position.. wright?

Zoom: what exactly do this parameter?? do a zoom.. ok.. but the value.. how is express?

F-number: so.. i haven't already understood how ths parameter work.. f/x.. ok.. small numbers gave a clearly image, large numbers geave a blurry image.. it's ok? so.. in internet.. i've read that the f-number are express usually in value that are similar to F1.4.. F2.0... and other.. but i'm not able to understand this.. anyone explane me how that work??

ISO: is the parameter that control how the light model the picture.. high value for very dark image.. right?

In depth of field.. if i check it.. i'm not able to change Aperture Value.. why this??

Center Bias: how work.. and what's its function?
Anisotropy: i think that's a filter for the image.. correct? how?
Subdivis: the value control the subdivision for the light?
Override focal distance: in inches format.. with this value.. regulate the distance where i want to be focused?? (sorry for the english.. :P) so.. if i put an object 1000inches far away from my camera.. and set unchecked override focal lenght in physical camera, and set 1000 for override focal distance in DOF control.. results that the object is focused.. and the rest blurry? why i'm not able to do?????? where i wrong??

Thanks a lot my friends.. and sorry for my (BAD) english.. and for the long text.. :P

[thomthom]

Re: How DOF and Physical Camera works??

Focal length is in millimeters not inches...Think of focal length as the Zoom on a camera.

Sorry, I meant Override Focal Dist. under the DOF section.

[dalomar_cg]

Re: How DOF and Physical Camera works??

If any value does not have a specific unit assigned to it, then it is always in scene units.

[thomthom]

Re: How DOF and Physical Camera works??

I might use scene units, but not as a user would expect. Internally SU uses inches, so you have to type all values in inches to V-Ray.
For me, who uses metric all the times, this took a while to get my head around as I couldn't make any sense of the values.