THIN LENS TAB

In Octane, camera options are divided into 5 separate TABs. These are; Thin Lens, Motion Blur, Camera Imager, Post Processing and Stereo. We will describe these tabs in chapters. Now let's start with Thinlens.



ABOUT DOF

In the following Thinlens description you will see some options for Depth of Field. So we want to briefly explain some terms. You can pass this article if you are familiar with DOF and its terms or topic.

Depth of Field (DOF for short) is the focus area on the front or back of the subject or person. If you can control the DOF, you could take the subject you want to photograph in the foreground as you would like. In this case, you can focus and pull the subject to the front by making the background blur.

The use of DOF is an important technique that must be used to better describe the desired context. When using this effect, at least decide what you want to tell. Do not get caught up in the popular appeal of DOF effects, as these daily renders or irrelevant everywhere.


The most important factor to control DOF is Aperture. The size of the DOF is inversely proportional to the aperture size. The more you open Aperture, the more the DOF is affected. That is, at low aperture values such as f/1.8 or f/2.8, the DOF becomes small. The aperture values such as f/16 or f/22, the greater the DOF.

In photography, the shallow, selective DOF separates the object in the foreground from the background and forms "Bokeh" spots, which are simply called "background blur". You will be able to observe this easily in Octane.




THIN LENS SETTINGS

Now Let's describe the Thinlens options.


Auto Focus

If enabled, the focus will be kept on the closest visible surface at the center of the image, regardless of the aperture, the aperture edge, and focal depth values. This setting is on by default. If you want to make manual focus, you can turn this option off. To do manual focus, you can press CTRL + MMB (middle mouse button) on the desired area in Live Viewer. Unless, of course, you make the "Aperture" option bigger than zero. If you do not want to make any focus, you can set "Aperture" to zero.


focal depth

The depth of the plane in focus, measured in meters. Focal Depth is also linked to Aperture and F-Stop. So focus will depend on the scene size and the size of the object. Also, when you are away from or near the object, all focus options are variable. Therefore, we recommend that you practice a lot.



aperture

The aperture is the radius of the lens opening of the camera used in the scene, measured in centimeters. Choosing a low value will have a wide depth of field where everything is in focus. Choosing a high value will create a shallow depth of field (DOF) where objects in the foreground and background will be out of focus. If you set Aperture to zero, you will no longer see the DOF effect. Everything is in focus.



f-stop

This is the aperture to focal length ratio. If you change Aperture, this value changes automatically; controls whether more light enters the camera lens.


aperture aspect ratio

This allows users to stretch/squash the Depth of Field disc.



aperture edge

This controls aperture edge detection at all points within the aperture. The lower values will give more pronounced edges to out of focus objects affected by the a shallow depth of field (DOF) such as objects in the foreground and background. The aperture edge modifies the bokeh effect of the depth of field. A high value increases the contrast towards the edge.


bokeh side count / bokeh rotation / bokeh roundedness

These three features work in conjunction with each other. Bokeh Side Count specifies how many bokehs in DOF will form, so you can determine the bokeh shape here. But when you change this setting, you may not notice a difference at first. This is because the default value of Bokeh Roundedness is 1. You can also change this setting according to the bokeh effect you want to see. Low values refer to a sharp bokeh shape. At higher values, the bokeh shape becomes smooth. Bokeh Rotation is used to rotate the bokeh shape. If you want the bokeh effect to be more pronounced, you can increase the Aperture setting.



perspective correction

If Up-vector is vertical, enabling this option keeps vertical lines parallel. This is useful for architectural rendering, when you want to render images of tall buildings from a similar height as the human eye, but keeping the vertical lines parallel.



near & far clip depth

The main purpose was for interior scenes where you want to get a good shot of the whole room but you cannot do so without a very large FOV, because you need to keep the camera inside the room. With camera clipping (near plane), you can position the camera outside the room - lower the FOV and increase the clipping plane distance in front of you until the closest walls are clipped out. The geometry is not altered, only the clipping of the camera, which means that shadows, reflections and refractions are still affected by the clipped geometry.



distortion

This adjusts the spherical and cylindrical distortion. The rendered image displays the entire sphere and uses equidistant cylindrical projection also known as lat-long projection.


orthographic

If enabled, the camera will render an orthographic view. If disabled, the camera will show a perspective view.


lens shift

Shift value for camera in film plane. It's very same as Film Offset X/Y in Cinema 4D camera. Also both parameters work in two ways.