diff --git a/src/ol/interaction/Draw.js b/src/ol/interaction/Draw.js
index 9b43feae21..b00c73f25c 100644
--- a/src/ol/interaction/Draw.js
+++ b/src/ol/interaction/Draw.js
@@ -110,7 +110,7 @@ import {fromUserCoordinate, getUserProjection} from '../proj.js';
  * geometry is the geometry that is returned when the function is called without
  * a second argument.
  * @typedef {function(!SketchCoordType, import("../geom/SimpleGeometry.js").default=,
- *     import("../proj/Projection.js").default):
+ *     import("../proj/Projection.js").default=):
  *     import("../geom/SimpleGeometry.js").default} GeometryFunction
  */
 
diff --git a/src/ol/source/ImageCanvas.js b/src/ol/source/ImageCanvas.js
index 2137d7aa6a..b0988f5f28 100644
--- a/src/ol/source/ImageCanvas.js
+++ b/src/ol/source/ImageCanvas.js
@@ -33,7 +33,7 @@ import ImageSource from './Image.js';
  * the value returned by the function is later changed then
  * `changed` should be called on the source for the source to
  * invalidate the current cached image. See: {@link module:ol/Observable~Observable#changed}
- * @property {import("../proj.js").ProjectionLike} projection Projection.
+ * @property {import("../proj.js").ProjectionLike} [projection] Projection. Default is the view projection.
  * @property {number} [ratio=1.5] Ratio. 1 means canvases are the size of the map viewport, 2 means twice the
  * width and height of the map viewport, and so on. Must be `1` or higher.
  * @property {Array<number>} [resolutions] Resolutions.
diff --git a/src/ol/source/ImageMapGuide.js b/src/ol/source/ImageMapGuide.js
index c47794c5ec..d39f82e111 100644
--- a/src/ol/source/ImageMapGuide.js
+++ b/src/ol/source/ImageMapGuide.js
@@ -20,7 +20,7 @@ import {appendParams} from '../uri.js';
  * @property {boolean} [hidpi=true] Use the `ol/Map#pixelRatio` value when requesting
  * the image from the remote server.
  * @property {boolean} [useOverlay] If `true`, will use `GETDYNAMICMAPOVERLAYIMAGE`.
- * @property {import("../proj.js").ProjectionLike} projection Projection.
+ * @property {import("../proj.js").ProjectionLike} [projection] Projection. Default is the view projection.
  * @property {number} [ratio=1] Ratio. `1` means image requests are the size of the map viewport, `2` means
  * twice the width and height of the map viewport, and so on. Must be `1` or higher.
  * @property {Array<number>} [resolutions] Resolutions.
diff --git a/src/ol/source/ImageStatic.js b/src/ol/source/ImageStatic.js
index 2df587238a..146a0fb1d5 100644
--- a/src/ol/source/ImageStatic.js
+++ b/src/ol/source/ImageStatic.js
@@ -19,7 +19,7 @@ import ImageSource, {defaultImageLoadFunction} from './Image.js';
  * @property {import("../extent.js").Extent} [imageExtent] Extent of the image in map coordinates.
  * This is the [left, bottom, right, top] map coordinates of your image.
  * @property {import("../Image.js").LoadFunction} [imageLoadFunction] Optional function to load an image given a URL.
- * @property {import("../proj.js").ProjectionLike} projection Projection.
+ * @property {import("../proj.js").ProjectionLike} [projection] Projection. Default is the view projection.
  * @property {import("../size.js").Size} [imageSize] Size of the image in pixels. Usually the image size is auto-detected, so this
  * only needs to be set if auto-detection fails for some reason.
  * @property {string} url Image URL.