diff --git a/libtiff/tif_aux.c b/libtiff/tif_aux.c
index 8188db53..c9f19054 100644
--- a/libtiff/tif_aux.c
+++ b/libtiff/tif_aux.c
@@ -270,7 +270,7 @@ TIFFVGetFieldDefaulted(TIFF* tif, uint32 tag, va_list ap)
 		return (1);
 	case TIFFTAG_EXTRASAMPLES:
 		*va_arg(ap, uint16 *) = td->td_extrasamples;
-		*va_arg(ap, uint16 **) = td->td_sampleinfo;
+		*va_arg(ap, const uint16 **) = td->td_sampleinfo;
 		return (1);
 	case TIFFTAG_MATTEING:
 		*va_arg(ap, uint16 *) =
@@ -292,8 +292,8 @@ TIFFVGetFieldDefaulted(TIFF* tif, uint32 tag, va_list ap)
 	case TIFFTAG_YCBCRCOEFFICIENTS:
 		{
 			/* defaults are from CCIR Recommendation 601-1 */
-			static float ycbcrcoeffs[] = { 0.299f, 0.587f, 0.114f };
-			*va_arg(ap, float **) = ycbcrcoeffs;
+			static const float ycbcrcoeffs[] = { 0.299f, 0.587f, 0.114f };
+			*va_arg(ap, const float **) = ycbcrcoeffs;
 			return 1;
 		}
 	case TIFFTAG_YCBCRSUBSAMPLING:
@@ -305,14 +305,14 @@ TIFFVGetFieldDefaulted(TIFF* tif, uint32 tag, va_list ap)
 		return (1);
 	case TIFFTAG_WHITEPOINT:
 		{
-			static float whitepoint[2];
-
 			/* TIFF 6.0 specification tells that it is no default
 			   value for the WhitePoint, but AdobePhotoshop TIFF
 			   Technical Note tells that it should be CIE D50. */
-			whitepoint[0] =	D50_X0 / (D50_X0 + D50_Y0 + D50_Z0);
-			whitepoint[1] =	D50_Y0 / (D50_X0 + D50_Y0 + D50_Z0);
-			*va_arg(ap, float **) = whitepoint;
+			static const float whitepoint[] = {
+						D50_X0 / (D50_X0 + D50_Y0 + D50_Z0),
+						D50_Y0 / (D50_X0 + D50_Y0 + D50_Z0)
+			};
+			*va_arg(ap, const float **) = whitepoint;
 			return 1;
 		}
 	case TIFFTAG_TRANSFERFUNCTION:
@@ -321,16 +321,16 @@ TIFFVGetFieldDefaulted(TIFF* tif, uint32 tag, va_list ap)
 			TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "No space for \"TransferFunction\" tag");
 			return (0);
 		}
-		*va_arg(ap, uint16 **) = td->td_transferfunction[0];
+		*va_arg(ap, const uint16 **) = td->td_transferfunction[0];
 		if (td->td_samplesperpixel - td->td_extrasamples > 1) {
-			*va_arg(ap, uint16 **) = td->td_transferfunction[1];
-			*va_arg(ap, uint16 **) = td->td_transferfunction[2];
+			*va_arg(ap, const uint16 **) = td->td_transferfunction[1];
+			*va_arg(ap, const uint16 **) = td->td_transferfunction[2];
 		}
 		return (1);
 	case TIFFTAG_REFERENCEBLACKWHITE:
 		if (!td->td_refblackwhite && !TIFFDefaultRefBlackWhite(td))
 			return (0);
-		*va_arg(ap, float **) = td->td_refblackwhite;
+		*va_arg(ap, const float **) = td->td_refblackwhite;
 		return (1);
 	}
 	return 0;
diff --git a/libtiff/tif_dir.c b/libtiff/tif_dir.c
index 998b69aa..d72414b4 100644
--- a/libtiff/tif_dir.c
+++ b/libtiff/tif_dir.c
@@ -1033,19 +1033,19 @@ _TIFFVGetField(TIFF* tif, uint32 tag, va_list ap)
 			*va_arg(ap, uint16*) = td->td_halftonehints[1];
 			break;
 		case TIFFTAG_COLORMAP:
-			*va_arg(ap, uint16**) = td->td_colormap[0];
-			*va_arg(ap, uint16**) = td->td_colormap[1];
-			*va_arg(ap, uint16**) = td->td_colormap[2];
+			*va_arg(ap, const uint16**) = td->td_colormap[0];
+			*va_arg(ap, const uint16**) = td->td_colormap[1];
+			*va_arg(ap, const uint16**) = td->td_colormap[2];
 			break;
 		case TIFFTAG_STRIPOFFSETS:
 		case TIFFTAG_TILEOFFSETS:
 			_TIFFFillStriles( tif );
-			*va_arg(ap, uint64**) = td->td_stripoffset_p;
+			*va_arg(ap, const uint64**) = td->td_stripoffset_p;
 			break;
 		case TIFFTAG_STRIPBYTECOUNTS:
 		case TIFFTAG_TILEBYTECOUNTS:
 			_TIFFFillStriles( tif );
-			*va_arg(ap, uint64**) = td->td_stripbytecount_p;
+			*va_arg(ap, const uint64**) = td->td_stripbytecount_p;
 			break;
 		case TIFFTAG_MATTEING:
 			*va_arg(ap, uint16*) =
@@ -1054,7 +1054,7 @@ _TIFFVGetField(TIFF* tif, uint32 tag, va_list ap)
 			break;
 		case TIFFTAG_EXTRASAMPLES:
 			*va_arg(ap, uint16*) = td->td_extrasamples;
-			*va_arg(ap, uint16**) = td->td_sampleinfo;
+			*va_arg(ap, const uint16**) = td->td_sampleinfo;
 			break;
 		case TIFFTAG_TILEWIDTH:
 			*va_arg(ap, uint32*) = td->td_tilewidth;
@@ -1089,7 +1089,7 @@ _TIFFVGetField(TIFF* tif, uint32 tag, va_list ap)
 			break;
 		case TIFFTAG_SUBIFD:
 			*va_arg(ap, uint16*) = td->td_nsubifd;
-			*va_arg(ap, uint64**) = td->td_subifd;
+			*va_arg(ap, const uint64**) = td->td_subifd;
 			break;
 		case TIFFTAG_YCBCRPOSITIONING:
 			*va_arg(ap, uint16*) = td->td_ycbcrpositioning;
@@ -1099,20 +1099,20 @@ _TIFFVGetField(TIFF* tif, uint32 tag, va_list ap)
 			*va_arg(ap, uint16*) = td->td_ycbcrsubsampling[1];
 			break;
 		case TIFFTAG_TRANSFERFUNCTION:
-			*va_arg(ap, uint16**) = td->td_transferfunction[0];
+			*va_arg(ap, const uint16**) = td->td_transferfunction[0];
 			if (td->td_samplesperpixel - td->td_extrasamples > 1) {
-				*va_arg(ap, uint16**) = td->td_transferfunction[1];
-				*va_arg(ap, uint16**) = td->td_transferfunction[2];
+				*va_arg(ap, const uint16**) = td->td_transferfunction[1];
+				*va_arg(ap, const uint16**) = td->td_transferfunction[2];
 			} else {
-				*va_arg(ap, uint16**) = NULL;
-				*va_arg(ap, uint16**) = NULL;
+				*va_arg(ap, const uint16**) = NULL;
+				*va_arg(ap, const uint16**) = NULL;
 			}
 			break;
 		case TIFFTAG_REFERENCEBLACKWHITE:
-			*va_arg(ap, float**) = td->td_refblackwhite;
+			*va_arg(ap, const float**) = td->td_refblackwhite;
 			break;
 		case TIFFTAG_INKNAMES:
-			*va_arg(ap, char**) = td->td_inknames;
+			*va_arg(ap, const char**) = td->td_inknames;
 			break;
 		default:
 			{
@@ -1154,7 +1154,7 @@ _TIFFVGetField(TIFF* tif, uint32 tag, va_list ap)
 							*va_arg(ap, uint32*) = (uint32)tv->count;
 						else  /* Assume TIFF_VARIABLE */
 							*va_arg(ap, uint16*) = (uint16)tv->count;
-						*va_arg(ap, void **) = tv->value;
+						*va_arg(ap, const void **) = tv->value;
 						ret_val = 1;
 					} else if (fip->field_tag == TIFFTAG_DOTRANGE
 						   && strcmp(fip->field_name,"DotRange") == 0) {
diff --git a/libtiff/tif_jpeg.c b/libtiff/tif_jpeg.c
index 93ae2ead..489e849e 100644
--- a/libtiff/tif_jpeg.c
+++ b/libtiff/tif_jpeg.c
@@ -2344,7 +2344,7 @@ JPEGVGetField(TIFF* tif, uint32 tag, va_list ap)
 	switch (tag) {
 		case TIFFTAG_JPEGTABLES:
 			*va_arg(ap, uint32*) = sp->jpegtables_length;
-			*va_arg(ap, void**) = sp->jpegtables;
+			*va_arg(ap, const void**) = sp->jpegtables;
 			break;
 		case TIFFTAG_JPEGQUALITY:
 			*va_arg(ap, int*) = sp->jpegquality;
diff --git a/libtiff/tif_ojpeg.c b/libtiff/tif_ojpeg.c
index b1f6a948..4b52e9f2 100644
--- a/libtiff/tif_ojpeg.c
+++ b/libtiff/tif_ojpeg.c
@@ -498,15 +498,15 @@ OJPEGVGetField(TIFF* tif, uint32 tag, va_list ap)
 			break;
 		case TIFFTAG_JPEGQTABLES:
 			*va_arg(ap,uint32*)=(uint32)sp->qtable_offset_count;
-			*va_arg(ap,void**)=(void*)sp->qtable_offset; 
+			*va_arg(ap,const void**)=(const void*)sp->qtable_offset;
 			break;
 		case TIFFTAG_JPEGDCTABLES:
 			*va_arg(ap,uint32*)=(uint32)sp->dctable_offset_count;
-			*va_arg(ap,void**)=(void*)sp->dctable_offset;  
+			*va_arg(ap,const void**)=(const void*)sp->dctable_offset;
 			break;
 		case TIFFTAG_JPEGACTABLES:
 			*va_arg(ap,uint32*)=(uint32)sp->actable_offset_count;
-			*va_arg(ap,void**)=(void*)sp->actable_offset;
+			*va_arg(ap,const void**)=(const void*)sp->actable_offset;
 			break;
 		case TIFFTAG_JPEGPROC:
 			*va_arg(ap,uint16*)=(uint16)sp->jpeg_proc;
diff --git a/man/TIFFGetField.3tiff b/man/TIFFGetField.3tiff
index c2fd025f..40f0323d 100644
--- a/man/TIFFGetField.3tiff
+++ b/man/TIFFGetField.3tiff
@@ -102,77 +102,77 @@ meaning of each tag and their possible values.
 .ta \w'TIFFTAG_CONSECUTIVEBADFAXLINES'u+2n +\w'Count'u+2n +\w'TIFFFaxFillFunc*'u+2n
 \fITag Name\fP	\fICount\fP	\fITypes\fP	\fINotes\fP
 .sp 5p
-TIFFTAG_ARTIST	1	char**
+TIFFTAG_ARTIST	1	const char**
 TIFFTAG_BADFAXLINES	1	uint32*
 TIFFTAG_BITSPERSAMPLE	1	uint16*
 TIFFTAG_CLEANFAXDATA	1	uint16*
-TIFFTAG_COLORMAP	3	uint16**	1<<BitsPerSample arrays
+TIFFTAG_COLORMAP	3	const uint16**	1<<BitsPerSample arrays
 TIFFTAG_COMPRESSION	1	uint16*
 TIFFTAG_CONSECUTIVEBADFAXLINES	1	uint32*
-TIFFTAG_COPYRIGHT	1	char**
+TIFFTAG_COPYRIGHT	1	const char**
 TIFFTAG_DATATYPE	1	uint16*
-TIFFTAG_DATETIME	1	char**
-TIFFTAG_DOCUMENTNAME	1	char**
+TIFFTAG_DATETIME	1	const char**
+TIFFTAG_DOCUMENTNAME	1	const char**
 TIFFTAG_DOTRANGE	2	uint16*
-TIFFTAG_EXTRASAMPLES	2	uint16*,uint16**	count & types array
+TIFFTAG_EXTRASAMPLES	2	uint16*,const uint16**	count & types array
 TIFFTAG_FAXFILLFUNC	1	TIFFFaxFillFunc*	G3/G4 compression pseudo-tag
 TIFFTAG_FAXMODE	1	int*	G3/G4 compression pseudo-tag
 TIFFTAG_FILLORDER	1	uint16*
 TIFFTAG_GROUP3OPTIONS	1	uint32*
 TIFFTAG_GROUP4OPTIONS	1	uint32*
 TIFFTAG_HALFTONEHINTS	2	uint16*
-TIFFTAG_HOSTCOMPUTER	1	char**
-TIFFTAG_ICCPROFILE	2	uint32*,void**	count, profile data
+TIFFTAG_HOSTCOMPUTER	1	const char**
+TIFFTAG_ICCPROFILE	2	const uint32*,const void**	count, profile data
 TIFFTAG_IMAGEDEPTH	1	uint32*
-TIFFTAG_IMAGEDESCRIPTION	1	char**
+TIFFTAG_IMAGEDESCRIPTION	1	const char**
 TIFFTAG_IMAGELENGTH	1	uint32*
 TIFFTAG_IMAGEWIDTH	1	uint32*
-TIFFTAG_INKNAMES	1	char**
+TIFFTAG_INKNAMES	1	const char**
 TIFFTAG_INKSET	1	uint16*
 TIFFTAG_JPEGCOLORMODE	1	int*	JPEG pseudo-tag
 TIFFTAG_JPEGQUALITY	1	int*	JPEG pseudo-tag
-TIFFTAG_JPEGTABLES	2	uint32*,void**	count & tables
+TIFFTAG_JPEGTABLES	2	uint32*,const void**	count & tables
 TIFFTAG_JPEGTABLESMODE	1	int*	JPEG pseudo-tag
-TIFFTAG_MAKE	1	char**
+TIFFTAG_MAKE	1	const char**
 TIFFTAG_MATTEING	1	uint16*
 TIFFTAG_MAXSAMPLEVALUE	1	uint16*
 TIFFTAG_MINSAMPLEVALUE	1	uint16*
-TIFFTAG_MODEL	1	char**
+TIFFTAG_MODEL	1	const char**
 TIFFTAG_ORIENTATION	1	uint16*
-TIFFTAG_PAGENAME	1	char**
+TIFFTAG_PAGENAME	1	const char**
 TIFFTAG_PAGENUMBER	2	uint16*
 TIFFTAG_PHOTOMETRIC	1	uint16*
-TIFFTAG_PHOTOSHOP	2	uint32*,void**	count, data
+TIFFTAG_PHOTOSHOP	2	uint32*,const void**	count, data
 TIFFTAG_PLANARCONFIG	1	uint16*
 TIFFTAG_PREDICTOR	1	uint16*
-TIFFTAG_PRIMARYCHROMATICITIES	1	float**	6-entry array
-TIFFTAG_REFERENCEBLACKWHITE	1	float**	6-entry array
+TIFFTAG_PRIMARYCHROMATICITIES	1	const float**	6-entry array
+TIFFTAG_REFERENCEBLACKWHITE	1	const float**	6-entry array
 TIFFTAG_RESOLUTIONUNIT	1	uint16*
-TIFFTAG_RICHTIFFIPTC	2	uint32*,void**	count, data
+TIFFTAG_RICHTIFFIPTC	2	uint32*,const void**	count, data
 TIFFTAG_ROWSPERSTRIP	1	uint32*
 TIFFTAG_SAMPLEFORMAT	1	uint16*
 TIFFTAG_SAMPLESPERPIXEL	1	uint16*
 TIFFTAG_SMAXSAMPLEVALUE	1	double*
 TIFFTAG_SMINSAMPLEVALUE	1	double*
-TIFFTAG_SOFTWARE	1	char**
-TIFFTAG_STONITS	1	double**
-TIFFTAG_STRIPBYTECOUNTS	1	uint32**
-TIFFTAG_STRIPOFFSETS	1	uint32**
+TIFFTAG_SOFTWARE	1	const char**
+TIFFTAG_STONITS	1	const double**
+TIFFTAG_STRIPBYTECOUNTS	1	const uint32**
+TIFFTAG_STRIPOFFSETS	1	const uint32**
 TIFFTAG_SUBFILETYPE	1	uint32*
-TIFFTAG_SUBIFD	2	uint16*,uint64**	count & offsets array
-TIFFTAG_TARGETPRINTER	1	char**
+TIFFTAG_SUBIFD	2	uint16*,const uint64**	count & offsets array
+TIFFTAG_TARGETPRINTER	1	const char**
 TIFFTAG_THRESHHOLDING	1	uint16*
-TIFFTAG_TILEBYTECOUNTS	1	uint32**
+TIFFTAG_TILEBYTECOUNTS	1	const uint32**
 TIFFTAG_TILEDEPTH	1	uint32*
 TIFFTAG_TILELENGTH	1	uint32*
-TIFFTAG_TILEOFFSETS	1	uint32**
+TIFFTAG_TILEOFFSETS	1	const uint32**
 TIFFTAG_TILEWIDTH	1	uint32*
-TIFFTAG_TRANSFERFUNCTION	1 or 3\(dg	uint16**1<<BitsPerSample entry arrays
-TIFFTAG_WHITEPOINT	1	float**	2-entry array
-TIFFTAG_XMLPACKET	2	uint32*,void**	count, data
+TIFFTAG_TRANSFERFUNCTION	1 or 3\(dg	const uint16**1<<BitsPerSample entry arrays
+TIFFTAG_WHITEPOINT	1	const float**	2-entry array
+TIFFTAG_XMLPACKET	2	uint32*,const void**	count, data
 TIFFTAG_XPOSITION	1	float*
 TIFFTAG_XRESOLUTION	1	float*
-TIFFTAG_YCBCRCOEFFICIENTS	1	float**	3-entry array
+TIFFTAG_YCBCRCOEFFICIENTS	1	const float**	3-entry array
 TIFFTAG_YCBCRPOSITIONING	1	uint16*
 TIFFTAG_YCBCRSUBSAMPLING	2	uint16*
 TIFFTAG_YPOSITION	1	float*