diff --git a/source/blender/src/drawimage.c b/source/blender/src/drawimage.c
index 89e34b6d73e..ac2b92d0815 100644
--- a/source/blender/src/drawimage.c
+++ b/source/blender/src/drawimage.c
@@ -2238,7 +2238,7 @@ void drawimagespace(ScrArea *sa, void *spacedata)
 							else if(ibuf->rect_float && ibuf->channels==4)
 								sima_draw_alpha_pixelsf(x1_rep, y1_rep, ibuf->x, ibuf->y, ibuf->rect_float);
 						}
-						else if(sima->flag & SI_SHOW_ZBUF && ((ibuf->zbuf || ibuf->zbuf_float || (ibuf->channels==1)) == 0)) {
+						else if(sima->flag & SI_SHOW_ZBUF && (ibuf->zbuf || ibuf->zbuf_float || (ibuf->channels==1))) {
 							if(ibuf->zbuf)
 								sima_draw_zbuf_pixels(x1_rep, y1_rep, ibuf->x, ibuf->y, ibuf->zbuf);
 							else if(ibuf->zbuf_float)
diff --git a/source/blender/src/header_image.c b/source/blender/src/header_image.c
index d4e5dd70777..bd170d646eb 100644
--- a/source/blender/src/header_image.c
+++ b/source/blender/src/header_image.c
@@ -1286,7 +1286,7 @@ void image_buttons(void)
 		}
 		if(ibuf) {
 			if(ibuf->zbuf || ibuf->zbuf_float || (ibuf->channels==1)) {
-				uiDefIconButBitI(block, TOG, SI_SHOW_ZBUF, B_SIMA_SHOW_ZBUF, ICON_SOLID, xco,0,XIC,YIC, &G.sima->flag, 0, 0, 0, 0, "Draws zbuffer values");
+				uiDefIconButBitI(block, TOG, SI_SHOW_ZBUF, B_SIMA_SHOW_ZBUF, ICON_SOLID, xco,0,XIC,YIC, &G.sima->flag, 0, 0, 0, 0, "Draws zbuffer values (mapped from camera clip start to end)");
 				xco+= XIC;
 			}
 		}