OTOY Forums

I am experimenting a lot and getting okay results with reasonable speed. But I feel a bit lost as to how to finely tune some of the camera settings.

Specifically ISO, aperture, and f-stop. Previously, I was told that aperture affects exposure and DOF, as is true in the real world. In practice, I do not see aperture affecting DOF much, if at all, in my experiments.

And, I remain confused by the focal depth setting. It seems to me to describe a characteristic that is already wholly determined by the aperture and focal length. I assume this setting refers to the distance between the front-most and rear-most planes of acceptable focus (ie, depth of field) and not to the distance of the prime point of focus from the plane of the imager.

I was also told that aperture, ISO, and f-stop effect exposure. Again, this is realistic. But, how do I know which of these to tweak? It feels to me like an arbitrary choice which one to alter to create a brighter scene, for example. In real life they have richer attributes it seems. For one thing, aperture and f-stop are bound together in real life. You cannot decrease your f-stop and increase your aperture, but Octane lets me do this! (I assume that this is because, unstated, Octane is letting me range among different format cameras and not impliedly enforcing specifications of a 35mm format camera. Is that correct? Are there more points of distinction between these settings in Octane than what I mention here?

Lastly, I was told that ISO effects noise. Of course, I assume that noise is also effected by anything that effects exposure, since lack of also light induces noise. Is this correct? Can I suppress noise by increasing the output of lights in my scene?

Hi gbambo,

The camera settings are more of a simulation than accurate real life modeling of camera behaviour, this could be part of your confusion.
You are right that some of these setting have a richer effect in real life photography.

The aperture and focal depth settings will not do anything with AutoFocus on so if this is on then that might explain the lack of change in your experiments.
Aperture in octanerender does not affect exposure. It affects the strength of the DOF only. The focal depth setting is the distance at which there is no DOF effect (what you are focusing on). As you point out, this is more accurately the focal LENGTH.

ISO, f-stop and exposure are effectively brightness controlls, desigend to be intuitive to those who are from a photography background.

In octanerender lighting and noise are a complicated issue. Lack of light intensity is not necessarily going to give you a noisy render. It is more to do with the size, position and number of light sources, and also the materials used in the scene. You can take a perfectly crisp render, change exposure, ISO and f-stop settings to make the render extremely dark and you will still have a crisp render.

Think of the exposure, iso and f-stop settings as more of a post processing effect, like you would do in photoshop. In the standalone version, none of these setting will restart the render process - indicating that they are simply taking the rendered image and adjusting the levels of it.

Hope that helps.

Cheers
Chris.

Thank you, very, very helpful.