diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index 5c9823a65738732c825b305b7e52d468ceb1e040..7dab18466c274fd4ce09cf0f2560efeac33b2dfb 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -572,8 +572,7 @@ static int tiff_unpack_strip(TiffContext *s, AVFrame *p, uint8_t *dst, int strid
 
 static int init_image(TiffContext *s, ThreadFrame *frame)
 {
-    int i, ret;
-    uint32_t *pal;
+    int ret;
 
     switch (s->planar * 1000 + s->bpp * 10 + s->bppcount) {
     case 11:
@@ -584,7 +583,7 @@ static int init_image(TiffContext *s, ThreadFrame *frame)
     case 21:
     case 41:
     case 81:
-        s->avctx->pix_fmt = AV_PIX_FMT_PAL8;
+        s->avctx->pix_fmt = s->palette_is_set ? AV_PIX_FMT_PAL8 : AV_PIX_FMT_GRAY8;
         break;
     case 243:
         if (s->photometric == TIFF_PHOTOMETRIC_YCBCR) {
@@ -651,14 +650,7 @@ static int init_image(TiffContext *s, ThreadFrame *frame)
     if ((ret = ff_thread_get_buffer(s->avctx, frame, 0)) < 0)
         return ret;
     if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8) {
-        if (s->palette_is_set) {
-            memcpy(frame->f->data[1], s->palette, sizeof(s->palette));
-        } else {
-            /* make default grayscale pal */
-            pal = (uint32_t *) frame->f->data[1];
-            for (i = 0; i < 1<<s->bpp; i++)
-                pal[i] = 0xFFU << 24 | i * 255 / ((1<<s->bpp) - 1) * 0x010101;
-        }
+        memcpy(frame->f->data[1], s->palette, sizeof(s->palette));
     }
     return 0;
 }