OTOY Forums

The way the camera aperture is implemented in 1.0 beta 2 is confusing. I figured it out without RTFMing, but probably only because I know what f numbers are, really. (I wrote that app.)

I'd like to see two changes:

1. The default scale on the aperture slider should be in f numbers. I guess it's nice to be able to have a mode where the slider is in the real units instead of the fraction we photographers like to use, but I for one will never use that mode. The ticks on the slider should give the common value sequence: 1, 1.4, 2, 2.8, 4, 5.6, etc.

2. It should default to f/22 or higher. I doubt most people want to see DoF blur in their initial render. They may open the aperture wider later to add DoF blur, but that's kind of an extra thing, don't you think? If you disagree, maybe you could compromise and start it at something more typical of a real camera, like f/2.8.

Hi,

the tonemapper F-Stop is not linked to the camera aperture radius of the camera lens for DOF currently.
it's better to be able to control those separately.

Radiance

would it be possible to save our own preferred default values?
lat/long, f stop etc

In the near future, you'll be able to save any node (or set of nodes) as a "macro". You'll then be able to quickly launch these macros to quickly create a node setup. This will assist in making favorite render set-ups, materials, environments, etc. readily available for other projects.

radiance wrote:the tonemapper F-Stop is not linked to the camera aperture radius of the camera lens for DOF currently.
it's better to be able to control those separately.

You've misunderstood. I wasn't talking about the tone mapper at all.

If you click on the Preview Camera icon in the Node Inspector, there's a slider called "aperture", defaulting to log scale values from 0.01 to 100.0. Smaller values give greater depth of field, whereas photographers think in terms of numbers ilke "f/4 and f/22" with larger numbers giving greater depth of field. Because I wrote a photographer's calculator, I understand that these are fractions, with f being the lens' focal length, so f/22 is actually a smaller number than f/4, but I don't think most of your program's users will know that. They'll expect that moving the slider to the right will increase the depth of field.

I'm also saying that a default aperture of 1.0 is too wide. It should be smaller, to give a greater default depth of field. DoF is something you normally decrease artistically only after you get everything framed right.

The only connection between the render camera and tone mapper settings I'm asking for is the behavior of the GUI slider control, not anything under the hood. That will all stay the same. In programming terms, they should both create separate instances of a common aperture slider control.

If the trouble is that you don't know how to convert the values under the hood, the f/Calc manual has all that. I believe the procedure would be to take FoV and the render frame size, use that to calculate the focal length, and divide the f number from the slider into the focal length to get the sort of values you're currently using for the aperture slider.

Incidentally, the tone mapper is confusing, too.

The aperture control there doesn't seem to control an optical aperture, except maybe in the sense used in photographic enlargers. By that I mean that it doesn't seem to affect the image's depth of field. It seems to be directly opposed by the exposure control, and if so, is redundant. Maybe I've missed something, and there's a physical explanation giving some difference between lowering exposure and increasing aperture in the tone mapper. Since you know I'm interested in photographic optics, you know I'd like to hear it.

I don't see why you need an ISO setting, either. In real-world photography, we have that control because it affects grain in film and noise in digital imagers, but what value does it have in computer renderings, where the imager is perfect? It doesn't change the film response setting. Is it redundant with respect to exposure, too? It seems so. If I double ISO and halve exposure, I can't see a difference in the image.

tangent wrote:The way the camera aperture is implemented in 1.0 beta 2 is confusing. …
I'd like to see two changes:
1. The default scale on the aperture slider should be in f numbers. I guess it's nice to be able to have a mode where the slider is in the real units instead of the fraction we photographers like to use, but I for one will never use that mode. The ticks on the slider should give the common value sequence: 1, 1.4, 2, 2.8, 4, 5.6, etc.

As a former photographer, I am QUITE agree with that!

As a former photographer, I am QUITE agree with that!

+1 It was confusing for me also

+1 , please do

+1

these are all user preferences, and i personally like to keep the system as it is now.
we are not all photographers, and i think having a system where the user simply can increase and decrease the depth of field in realtime, while seeing the result is also easier than having to give them camera controls...

also, i have certain things in mind for the future with regards to the nodegraph and it's use that will make these things very difficult to integrate, but one could make something like this himself in the near future.

Radiance