Lens Tab ‐ Lens Settings - ApertureViewer/Aperture-Viewer GitHub Wiki

The Lens Tab in the Aperture Phototools Suite (APS) groups settings that simulate real-world camera lens effects, including Depth of Field (DOF), Glow, and Chromatic Aberration.

Depth of Field Settings

Depth of Field (DOF) simulates the photographic effect where only a certain range of distances from the camera appears in sharp focus, while closer and farther objects appear blurred.

Enabling DOF and Focus Aids

  • Enable Depth of Field:
    • Function: Checkbox to toggle the DOF effect on or off. The controls below are disabled if DOF is off.
  • Depth of Field focus follows pointer:
    • Function: When checked, the point of sharpest focus for DOF will automatically follow your mouse cursor as you move it over objects in the scene.

[!TIP] This is very useful for quickly setting focus when using the standard viewer camera. If using a 3D mouse (joystick/flycam), DOF often follows the flycam's focal point by default.

  • Toggle focus point crosshair:
    • Function: A toggle button (icon resembling a target) that shows or hides an on-screen crosshair indicating the current DOF focus point.
    • Visual Feedback: The crosshair is typically yellow when the focus is free-floating (e.g., following the pointer) and turns red when the focus point has been locked.

[!NOTE] Focus can be locked using a keystroke (customizable in Preferences -> Keys & Movement -> Camera). Improving the intuitiveness of locking focus is an area for future development, potentially with right-click context menu options or a dedicated UI button for locking/unlocking the current focus distance.

  • Keep DoF enabled in Edit Mode:
    • Function: When checked, DOF effects will remain active even when you enter Edit mode for building or manipulating objects. By default, DOF is often disabled in Edit mode.

DOF Parameters

These sliders control the characteristics of the DOF effect.

  • Camera Angle:
    • Function: Primarily affects the Field of View (FOV) when using the standard viewer camera controls (not flycam/joystick). It influences the perceived zoom and thereby the DOF.
    • Range: 0.001 to 3.0.
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
  • FOV (Field of View):
    • Function: Directly controls the camera's Field of View in degrees. A smaller FOV (telephoto effect) generally results in a shallower DOF, while a larger FOV (wide-angle effect) results in a deeper DOF, all else being equal.
    • Range: 0.1 to 180 degrees.
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.

[!NOTE] Aperture Viewer has unlocked the min/max values for this slider, allowing for more extreme zoom (very narrow FOV) and wider wide-angle views compared to some viewers.

  • f-number:
    • Function: Simulates the aperture setting (f-stop) of a real lens. Lower f-numbers (e.g., f/1.4) produce a shallower DOF (more background/foreground blur). Higher f-numbers (e.g., f/16) produce a deeper DOF (more of the scene in focus).
    • Range: 0.01 to 22.0.
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
  • Foc Length (Focal Length):
    • Function: Simulates the focal length of a real lens in millimeters. Longer focal lengths (e.g., 200mm) generally result in a shallower DOF and more background compression. Shorter focal lengths (e.g., 24mm) result in a deeper DOF and a wider view.
    • Range: 1 to 300 mm.
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.

[!IMPORTANT] The FOV (Field of View), f-number, and Foc Length (Focal Length) sliders are highly interdependent in how they affect DOF, much like in real photography. For simplified DOF control in Aperture:

  1. Set f-number all the way to its minimum (e.g., 0.01).
  2. Set Foc Length all the way to its minimum (e.g., 1).
  3. Then, primarily use the FOV slider to adjust the strength and appearance of your DOF effect. This approach often provides more intuitive and direct control over the blur. Future Aperture versions may further simplify or correct the DOF system to be more aligned with real-world lens behavior, possibly by reducing the number of interacting controls.
  • Foc Time (Focus Transition Time):
    • Function: Controls the speed at which the focus point transitions when it changes (e.g., when "Depth of Field focus follows pointer" is enabled and you move your cursor). Higher values result in a slower, smoother focus pull.
    • Range: 0.0 (instant) to 5.0 seconds.
    • Default Reset Button (D): Resets to 0.0.

[!TIP] A non-zero Focus Time can be useful for cinematic focus pulls in machinima. For still photography, 0.0 is usually preferred for responsiveness.

  • CoC (Max Circle of Confusion):
    • Function: Determines the maximum size of the "circle of confusion," which dictates how blurry out-of-focus areas become. Higher values result in more intense blur.
    • Range: 0.1 to 150.0.
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
  • Resolution:
    • Function: Controls the rendering resolution of the DOF effect itself. Higher values can produce smoother, higher-quality blur but may have a greater performance impact.
    • Range: 0.0 (lowest quality/performance) to 1.0 (highest quality/performance).
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset (often around 0.7 for a balance).

[!NOTE] In high-resolution snapshots, the difference between 0.7 and 1.0 DOF resolution may be negligible, but 1.0 can be used for maximum quality if performance allows.

Glow Settings

Glow adds a luminous halo effect around bright objects or areas in the scene.

Enabling Glow

  • Enable Glow Effect:
    • Function: Checkbox to toggle the glow post-processing effect on or off.
  • Enable HDR Glow Map:
    • Function: When checked, utilizes an HDR (High Dynamic Range) texture map for the glow calculations, potentially offering a wider range of brightness in the glow. Its visual impact can be subtle.
  • Enable Glow Noise:
    • Function: When checked, adds a noise pattern to the glow, which can give it a more organic or film-like appearance.

Glow Parameters

These sliders adjust the characteristics of the glow effect when enabled.

  • Glow Quality:
    • Function: An exclusive Aperture Viewer control that allows adjustment of the glow map's resolution. It's presented as a power-of-two exponent (8 to 13, where 2^8=256, 2^13=8192). Higher values result in a higher resolution glow map, which can lead to smoother and more detailed glows, especially for large or complex emissive sources, but will consume more video memory.
    • Range: 8 (e.g., 256x256) to 13 (e.g., 8192x8192).
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
  • Iterations:
    • Function: Controls the number of passes or samples used to generate the glow. More iterations can lead to a smoother, more refined glow but will increase performance cost.
    • Range: 1 to 128.
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
  • Strength:
    • Function: Adjusts the overall intensity or brightness of the glow effect.
    • Range: 0.0 to 0.5 (though the spinner allows higher values, the effective visual range on the slider is optimized).
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
  • Width:
    • Function: Controls how far the glow spreads out from the source pixels.
    • Range: 0.0 to 2.0.
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
  • Lum Min (Minimum Luminance):
    • Function: Sets a threshold; only pixels brighter than this luminance value will contribute to the glow effect. This helps to isolate glow to truly bright areas.
    • Range: 0.0 (all pixels can glow) to 1.0 (only extremely bright pixels glow).
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.

[!NOTE] This setting, along with "Alpha Limit," was re-implemented in Aperture Viewer, as similar controls had been removed or altered in the base viewer code over time, restoring finer control over what contributes to the glow effect.

  • Alpha Limit:
    • Function: Sets an upper threshold on the alpha (transparency) of pixels that contribute to glow. This can prevent very transparent but bright objects from producing overly strong glows.
    • Range: 0.0 to 1.0.
    • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.

Chromatic Aberration Settings

Chromatic Aberration (CA) is an optical effect where a lens fails to focus all colors to the same convergence point, resulting in color fringing, typically seen at the edges of high-contrast areas. In APS, this is offered as a creative effect.

  • CA Red/Cyan:
    • Function: Controls the amount of radial color fringing along the Red/Cyan axis. Positive values shift red outwards and cyan inwards; negative values do the opposite.
    • Range: -50.0 to 50.0.
    • Default Reset Button (D): Resets to 0.0.
  • CA Grn/Mag (Green/Magenta):
    • Function: Controls the amount of radial color fringing along the Green/Magenta axis.
    • Range: -50.0 to 50.0.
    • Default Reset Button (D): Resets to 0.0.
  • CA Blue/Yel (Blue/Yellow):
    • Function: Controls the amount of radial color fringing along the Blue/Yellow axis.
    • Range: -50.0 to 50.0.
    • Default Reset Button (D): Resets to 0.0.
  • CA Softness:
    • Function: Adjusts the softness or blurriness of the color fringes. Higher values create a more diffused, less sharp fringing effect.
    • Range: 0.0 (sharp fringes) to 1.0 (very soft fringes).
    • Default Reset Button (D): Resets to 0.0.

[!TIP] Chromatic Aberration can be used subtly to add a filmic or imperfect lens quality to images, or more extremely for stylized effects. Combining it with Film Grain (on the Post-Processing tab) can enhance vintage or analog aesthetics. It's often most noticeable in black and white images where the color separation becomes very apparent.