title: How can i get 35 focal lenght from photo properties?
body: <p>I work with camera2API and i need to get <code>focal lenght</code> property.</p>
  
  <p>I found one way to get it from camera characteristic</p>
  
  <pre><code>float[] f = characteristics.get(CameraCharacteristics.LENS_INFO_AVAILABLE_FOCAL_LENGTHS);
  
              for (float d : f) {
                  Logger.logGeneral("LENS_INFO_AVAILABLE_FOCAL_LENGTHS : " + d);
              }
  </code></pre>
  
  <p>but this approach retern back value like <code>3.8</code> or smth close to it. It depend of the device. But this value have to be approximately close to <code>30-35</code>...</p>
  
  <p>Then i found another solution. When i take a photo i opened photo properties and saw exextly what i get and what i need</p>
  
  <p><a href="https://i.stack.imgur.com/e7k8L.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/e7k8L.jpg" alt="enter image description here"></a></p>
  
  <p>I tryed to get this property directly from image</p>
  
  <pre><code>private JSONObject getJsonProperties() {
      JSONObject properties = new JSONObject();
  
      final ExifInterface exif = getExifInterface();
      final String [] tagProperties = {TAG_DATETIME, TAG_DATETIME_DIGITIZED, TAG_EXPOSURE_TIME,
              TAG_FLASH, TAG_FOCAL_LENGTH, TAG_GPS_ALTITUDE, TAG_GPS_ALTITUDE_REF, TAG_GPS_DATESTAMP,
              TAG_GPS_LATITUDE, TAG_GPS_LATITUDE_REF, TAG_GPS_LONGITUDE, TAG_GPS_LONGITUDE_REF,
              TAG_GPS_PROCESSING_METHOD, TAG_GPS_TIMESTAMP, TAG_IMAGE_LENGTH, TAG_IMAGE_WIDTH, TAG_ISO, TAG_MAKE,
              TAG_MODEL, TAG_ORIENTATION, TAG_SUBSEC_TIME, TAG_SUBSEC_TIME_DIG, TAG_SUBSEC_TIME_ORIG, TAG_WHITE_BALANCE};
  
      for (String tag : tagProperties){
          try {
              properties.put(tag, exif.getAttribute(tag));
          } catch (JSONException e) {
              e.printStackTrace();
          }
      }
  
      return properties;
  }
  
  private ExifInterface getExifInterface() {
      ExifInterface exif = null;
      try {
          exif = new ExifInterface(ImageSaver.getImageFilePath());
      } catch (IOException e) {
          e.printStackTrace();
      }
      return exif;
  }
  </code></pre>
  
  <p>I combine set of entire properties and of course include one that i very need <code>TAG_FOCAL_LENGTH</code>. But again i get wrong valeu like this <code>473/100</code>... i don't know what does it mean... Valeu have to be approximatly <code>30-35</code>...</p>
  
  <p>What am i doing wrong?</p>