diff --git a/src/integrators/photonmapper/photonmapper.cpp b/src/integrators/photonmapper/photonmapper.cpp
index 38e6ecc8..dc4e0d7e 100644
--- a/src/integrators/photonmapper/photonmapper.cpp
+++ b/src/integrators/photonmapper/photonmapper.cpp
@@ -207,7 +207,7 @@ public:
 		bool hasDelta = false;
 		for (size_t i=0; i<scene->getShapes().size(); ++i) {
 			const BSDF *bsdf = scene->getShapes()[i]->getBSDF();
-			if (bsdf->getType() & BSDF::EDelta)
+			if (bsdf && bsdf->getType() & BSDF::EDelta)
 				hasDelta = true;
 		}