--- /misha/ports/devel/tcllib/work/tcllib-1.6/modules/exif/exif.tcl	Sun Feb 15 18:15:51 2004
+++ /opt/lib/tcllib1.6/exif/exif.tcl	Wed Sep 15 12:24:22 2004
@@ -530,12 +530,15 @@
                     }]
                     # Field 18 - unknown
-                    set result(AFPoint) [switch -- [expr {$field(19)-0x3000}] {
-                        0 {format none}
-                        1 {format auto-selected}
-                        2 {format right}
-                        3 {format center}
-                        4 {format left}
-                        default {format unknown}
-                    }] ; # {}
+                    if {[info exists field(19)]} {
+                        set result(AFPoint) \
+                            [switch -- [expr {$field(19)-0x3000}] {
+                                0 {format none}
+                                1 {format auto-selected}
+                                2 {format right}
+                                3 {format center}
+                                4 {format left}
+                                default {format unknown}
+                            }]
+                    }
 		    if {[info exists field(20)]} {
 			if {$field(20) == 0} {
