Trim null characters from the end of ascii fields only when available.

And take all characters into account.

src/PelIfd.php

@@ -424,7 +424,7 @@ public function newEntryFromData($tag, $format, $components, PelDataWindow $data
                         return $v;
 
                     case PelFormat::ASCII:
-                        return new PelEntryAscii($tag, rtrim($data->getBytes(0, - 1), "\0"));
+                        return new PelEntryAscii($tag, rtrim($data->getBytes(0), "\0"));
 
                     case PelFormat::SHORT:
                         $v = new PelEntryShort($tag);