diff --git a/autotest/gcore/tiff_write.py b/autotest/gcore/tiff_write.py
index baab96cfff06..f803b95d24b8 100755
--- a/autotest/gcore/tiff_write.py
+++ b/autotest/gcore/tiff_write.py
@@ -9784,6 +9784,39 @@ def test_tiff_write_jpegxl_five_bands_lossless(tmp_vsimem):
         assert ds.GetRasterBand(i + 1).Checksum() == 4672
 
 
+###############################################################################
+
+
+@pytest.mark.require_creation_option("GTiff", "JXL")
+def test_tiff_write_jpegxl_float16(tmp_vsimem):
+
+    outfilename = str(tmp_vsimem / "test_tiff_write_jpegxl_float16")
+    src_ds = gdal.Open("data/float16.tif")
+    gdal.GetDriverByName("GTiff").CreateCopy(
+        outfilename, src_ds, options=["COMPRESS=JXL", "JXL_LOSSLESS=YES"]
+    )
+    ds = gdal.Open(outfilename)
+    assert ds.GetRasterBand(1).DataType == gdal.GDT_Float32
+    assert ds.GetRasterBand(1).GetMetadataItem("NBITS", "IMAGE_STRUCTURE") == "16"
+    assert ds.GetRasterBand(1).Checksum() == 4672
+
+
+###############################################################################
+
+
+@pytest.mark.require_creation_option("GTiff", "JXL")
+@pytest.mark.parametrize("dt,nbits", [(gdal.GDT_Float64, None), (gdal.GDT_Byte, 1)])
+@gdaltest.enable_exceptions()
+def test_tiff_write_jpegxl_errors(tmp_vsimem, dt, nbits):
+
+    outfilename = str(tmp_vsimem / "test_tiff_write_jpegxl_errors")
+    with pytest.raises(Exception):
+        options = {"COMPRESS": "JXL"}
+        if nbits:
+            options["NBITS"] = str(nbits)
+        gdal.GetDriverByName("GTiff").Create(outfilename, 1, 1, 1, dt, options=options)
+
+
 ###############################################################################
 # Test creating overviews with NaN nodata
 
diff --git a/frmts/gtiff/geotiff.cpp b/frmts/gtiff/geotiff.cpp
index 854c9cf91b7b..877feb1dc7e7 100644
--- a/frmts/gtiff/geotiff.cpp
+++ b/frmts/gtiff/geotiff.cpp
@@ -983,6 +983,7 @@ static void GTiffTagExtender(TIFF *tif)
 static std::mutex oDeleteMutex;
 #ifdef HAVE_JXL
 static TIFFCodec *pJXLCodec = nullptr;
+static TIFFCodec *pJXLCodecDNG17 = nullptr;
 #endif
 
 void GTiffOneTimeInit()
@@ -1000,6 +1001,8 @@ void GTiffOneTimeInit()
     if (pJXLCodec == nullptr)
     {
         pJXLCodec = TIFFRegisterCODEC(COMPRESSION_JXL, "JXL", TIFFInitJXL);
+        pJXLCodecDNG17 =
+            TIFFRegisterCODEC(COMPRESSION_JXL_DNG_1_7, "JXL", TIFFInitJXL);
     }
 #endif
 
@@ -1024,6 +1027,9 @@ static void GDALDeregister_GTiff(GDALDriver *)
     if (pJXLCodec)
         TIFFUnRegisterCODEC(pJXLCodec);
     pJXLCodec = nullptr;
+    if (pJXLCodecDNG17)
+        TIFFUnRegisterCODEC(pJXLCodecDNG17);
+    pJXLCodecDNG17 = nullptr;
 #endif
 }
 
@@ -1058,6 +1064,7 @@ static const struct
     {COMPRESSION_LERC, "LERC_ZSTD", true},
     COMPRESSION_ENTRY(WEBP, true),
     COMPRESSION_ENTRY(JXL, true),
+    COMPRESSION_ENTRY(JXL_DNG_1_7, true),
 
     // Compression methods in read-only
     COMPRESSION_ENTRY(OJPEG, false),
diff --git a/frmts/gtiff/gtiffdataset_write.cpp b/frmts/gtiff/gtiffdataset_write.cpp
index e9ee1ad95219..bac9d8eb3b92 100644
--- a/frmts/gtiff/gtiffdataset_write.cpp
+++ b/frmts/gtiff/gtiffdataset_write.cpp
@@ -5252,10 +5252,10 @@ TIFF *GTiffDataset::CreateLL(const char *pszFilename, int nXSize, int nYSize,
     }
 
 #ifdef HAVE_JXL
-    if (l_nCompression == COMPRESSION_JXL)
+    if (l_nCompression == COMPRESSION_JXL && eType != GDT_Float32)
     {
         // Reflects tif_jxl's GetJXLDataType()
-        if (eType != GDT_Byte && eType != GDT_UInt16 && eType != GDT_Float32)
+        if (eType != GDT_Byte && eType != GDT_UInt16)
         {
             ReportError(pszFilename, CE_Failure, CPLE_NotSupported,
                         "Data type %s not supported for JXL compression. Only "
@@ -5271,7 +5271,6 @@ TIFF *GTiffDataset::CreateLL(const char *pszFilename, int nXSize, int nYSize,
         } asSupportedDTBitsPerSample[] = {
             {GDT_Byte, 8},
             {GDT_UInt16, 16},
-            {GDT_Float32, 32},
         };
 
         for (const auto &sSupportedDTBitsPerSample : asSupportedDTBitsPerSample)
diff --git a/frmts/gtiff/libtiff/tiff.h b/frmts/gtiff/libtiff/tiff.h
index d8da33dc3837..980e8e8f52bb 100644
--- a/frmts/gtiff/libtiff/tiff.h
+++ b/frmts/gtiff/libtiff/tiff.h
@@ -216,6 +216,7 @@ typedef enum
 #define COMPRESSION_ZSTD 50000             /* ZSTD: WARNING not registered in Adobe-maintained registry */
 #define COMPRESSION_WEBP 50001             /* WEBP: WARNING not registered in Adobe-maintained registry */
 #define COMPRESSION_JXL 50002              /* JPEGXL: WARNING not registered in Adobe-maintained registry */
+#define COMPRESSION_JXL_DNG_1_7 52546      /* JPEGXL from DNG 1.7 specification */
 #define TIFFTAG_PHOTOMETRIC 262            /* photometric interpretation */
 #define PHOTOMETRIC_MINISWHITE 0           /* min value is white */
 #define PHOTOMETRIC_MINISBLACK 1           /* min value is black */
diff --git a/frmts/gtiff/tif_jxl.c b/frmts/gtiff/tif_jxl.c
index 940808bafe35..4634fad4558d 100644
--- a/frmts/gtiff/tif_jxl.c
+++ b/frmts/gtiff/tif_jxl.c
@@ -98,8 +98,16 @@ static int GetJXLDataType(TIFF *tif)
         return JXL_TYPE_FLOAT;
     }
 
-    TIFFErrorExtR(tif, module,
-                  "Unsupported combination of SampleFormat and BitsPerSample");
+    if (td->td_sampleformat == SAMPLEFORMAT_IEEEFP &&
+        td->td_bitspersample == 16)
+    {
+        return JXL_TYPE_FLOAT16;
+    }
+
+    TIFFErrorExtR(
+        tif, module,
+        "Unsupported combination of SampleFormat(=%d) and BitsPerSample(=%d)",
+        td->td_sampleformat, td->td_bitspersample);
     return -1;
 }
 
@@ -113,6 +121,8 @@ static int GetJXLDataTypeSize(JxlDataType dtype)
             return 2;
         case JXL_TYPE_FLOAT:
             return 4;
+        case JXL_TYPE_FLOAT16:
+            return 2;
         default:
             return 0;
     }
@@ -811,7 +821,10 @@ static int JXLPostEncode(TIFF *tif)
     basic_info.orientation = JXL_ORIENT_IDENTITY;
     if (td->td_sampleformat == SAMPLEFORMAT_IEEEFP)
     {
-        basic_info.exponent_bits_per_sample = 8;
+        if (td->td_bitspersample == 32)
+            basic_info.exponent_bits_per_sample = 8;
+        else
+            basic_info.exponent_bits_per_sample = 5;
     }
     else
     {
@@ -1275,7 +1288,7 @@ int TIFFInitJXL(TIFF *tif, int scheme)
     JXLState *sp;
 
     (void)scheme;
-    assert(scheme == COMPRESSION_JXL);
+    assert(scheme == COMPRESSION_JXL || scheme == COMPRESSION_JXL_DNG_1_7);
 
     /*
      * Merge codec-specific tag information.
diff --git a/frmts/gtiff/tif_jxl.h b/frmts/gtiff/tif_jxl.h
index 6e80cd459cdb..2827322c7541 100644
--- a/frmts/gtiff/tif_jxl.h
+++ b/frmts/gtiff/tif_jxl.h
@@ -30,6 +30,10 @@
     50002 /* JPEGXL: WARNING not registered in Adobe-maintained registry */
 #endif
 
+#ifndef COMPRESSION_JXL_DNG_1_7
+#define COMPRESSION_JXL_DNG_1_7 52546 /* JPEGXL from DNG 1.7 specification */
+#endif
+
 #ifndef TIFFTAG_JXL_LOSSYNESS
 
 /* Pseudo tags */