diff --git a/src/pbrt/film.cpp b/src/pbrt/film.cpp
index 277e750d84cf08792c2d9ecc82468497b29a8fc4..1e28313ccfc572642b5c43b74ee6a3626948c835 100644
--- a/src/pbrt/film.cpp
+++ b/src/pbrt/film.cpp
@@ -868,9 +868,9 @@ SpectralFilm::SpectralFilm(FilmBaseParameters p, Float lambdaMin, Float lambdaMa
     for (Point2i p : pixelBounds) {
         Pixel &pixel = pixels[p];
         pixel.bucketSums = bucketWeightBuffer;
-        bucketWeightBuffer += NSpectrumSamples;
+        bucketWeightBuffer += nBuckets;
         pixel.weightSums = bucketWeightBuffer;
-        bucketWeightBuffer += NSpectrumSamples;
+        bucketWeightBuffer += nBuckets;
         pixel.bucketSplats = splatBuffer;
         splatBuffer += NSpectrumSamples;
     }