What does F/stop do?

odastein

I tried to change F/stop to a lower value in tone mapping, hoping to reduce the depth of field. But instead, I got a brightly illuminated scene. So, what does this control do????

odastein

OK, I see there are in fact *two* F/stop controls. One in the "tone mapping" tab, which I tried to change (default is 8) and another in the parameters/camera tab (default : 22). So, other question : what's the difference?????

vwrangler

odastein said:

OK, I see there are in fact *two* F/stop controls. One in the "tone mapping" tab, which I tried to change (default is 8) and another in the parameters/camera tab (default : 22). So, other question : what's the difference?????

The f-stop in the Parameters tab/camera does what you wanted in your first question. It's related to depth of field, which should be active for the parmeters f-stop to work as well as it can. It also works with the other Parameters tab settings for the camera to do what it does. In perspective view, you can zoom out on your scene and, with the camera selected, you'll see red/white borders that will tell you where the sharply focused areas start and end, and where depth of field will take over and stop focusing on things beyond those red/white borders.

The f-stop in the tone mapping settings on the render tab controls the size of the aperture in your virtual camera, which is what something called "f-stop" is supposed to do. Basically, the lower the number in the f-stop in render settings, the more light you'll see in your render. Lower numbers are best used for lower light situations.

marcelle19

I realize this is an old thread, but it came up when I did a search for "F.Stop Daz Studio."

How, exactly, does the F/Stop in the Perimeters Tab work? I was told somewhere else that placing a higher number in that adjustment made the scene have more light.

Thank you.

Gordig

marcelle19 said:

How, exactly, does the F/Stop in the Perimeters Tab work? I was told somewhere else that placing a higher number in that adjustment made the scene have more light.

The f-stop control in the Parameters pane controls depth of field; the f-stop in Render Settings changes the exposure value, affecting the brightness of light.

Chezjuan

As noted above, the parameters f/stop has no effect on the light levels of a render. It controls Depth of Field (DoF), which is essentially the area of focus for a render.

Specifically, it controls the size of the focal plane - the area in which all objects are in focus from the camera's viewpoint. The lower the number, the smaller the focal plane, and the more blur you get on objects not in the plane. In conjunction with Focal Distance, which controls the position of the focal plane, you can create varying levels of blur in your image, mimicing the functionality of a Single Lens Reflex (SLR) camera.

If you add a camera to your scene and select it in the Scene tab, then switch the viewport to another camera or to perspective view, you can see the focal plane. It is two white squares in the marked camera view with a colored cross inbetween them. Changing focal distance will move where the two squares are relative to the camera, and changing f/stop changes the distance between the two squares. You position the colored cross where you want the focus, and objects outside of the two squares will have varying degrees of blur based on the f/stop selected.

This image has a low parameters f/stop number, which creates a lot of blur in the background:

If you are looking to change light levels using f/stop, you need to use the one in tone mapping or render settings. Again, it works like a SLR camera - the lower the number the more light. You can also change Shutter Speed and Film ISO to change light levels. Lower shutter speed means more light, and higher Film ISO means more light. There are some cases where this is useful, and others where you may just want to add more lights to a scene.