diff --git a/src/renderers/shaders/ShaderChunk/logdepthbuf_fragment.glsl.js b/src/renderers/shaders/ShaderChunk/logdepthbuf_fragment.glsl.js
index 1ab95c428e95d7..3da54de9a7a2bb 100644
--- a/src/renderers/shaders/ShaderChunk/logdepthbuf_fragment.glsl.js
+++ b/src/renderers/shaders/ShaderChunk/logdepthbuf_fragment.glsl.js
@@ -3,7 +3,7 @@ export default /* glsl */`
 
 	// Doing a strict comparison with == 1.0 can cause noise artifacts
 	// on some platforms. See issue #17623.
-	gl_FragDepthEXT = vIsPerspective == 0.0 ? gl_FragCoord.z : log2( vFragDepth ) * logDepthBufFC * 0.5;
+	gl_FragDepthEXT = vIsPerspective == 0.0 ? vFragDepth : log2( vFragDepth ) * logDepthBufFC * 0.5;
 
 #endif
 `;
diff --git a/src/renderers/shaders/ShaderChunk/logdepthbuf_vertex.glsl.js b/src/renderers/shaders/ShaderChunk/logdepthbuf_vertex.glsl.js
index e1b4d21e074820..00834f67cca5ae 100644
--- a/src/renderers/shaders/ShaderChunk/logdepthbuf_vertex.glsl.js
+++ b/src/renderers/shaders/ShaderChunk/logdepthbuf_vertex.glsl.js
@@ -3,8 +3,11 @@ export default /* glsl */`
 
 	#ifdef USE_LOGDEPTHBUF_EXT
 
-		vFragDepth = 1.0 + gl_Position.w;
-		vIsPerspective = float( isPerspectiveMatrix( projectionMatrix ) );
+		bool isPerspective = isPerspectiveMatrix( projectionMatrix );
+
+		vIsPerspective = float( isPerspective );
+
+		vFragDepth = isPerspective ? 1.0 + gl_Position.w : gl_Position.z * 0.5 + 0.5;
 
 	#else