diff --git a/ext/exif/exif.c b/ext/exif/exif.c
index 2618d749a3f..d5271e774e8 100644
--- a/ext/exif/exif.c
+++ b/ext/exif/exif.c
@@ -1918,7 +1918,7 @@ static void exif_iif_add_value(image_info_type *image_info, int section_index, c
 		case TAG_FMT_UNDEFINED:
 			if (value) {
 				if (tag == TAG_MAKER_NOTE) {
-					length = MIN(length, strlen(value));
+					length = MIN(length, (int) strlen(value));
 				}
 
 				/* do not recompute length here */