Exif Flag FocalLength cant be set

[MaxKrapp]

Hello I try to set my FocalLength exif parameter using

 `def setImageMeta(image_path, make = u"Basler", model = u"acA2440-35um", focal_length = 4, sensor_width = 8.4, max_image_circle = "2/3\""):
    o = io.BytesIO()
    thumb_im = Image.open(image_path)
    width, height = thumb_im.size
    width = int(width *0.5)
    height = int(height * 0.5)
    thumb_im.thumbnail((width,height), Image.ANTIALIAS)
    thumb_im.save(o, "jpeg")
    thumbnail = o.getvalue()

zeroth_ifd = {piexif.ImageIFD.Make: u"Basler",
          piexif.ImageIFD.Software: u"Inveox"
          }
exif_ifd = {
            #piexif.ExifIFD.LensMake: "LensMake",
            piexif.ExifIFD.FocalLength: 8/1,
            }
gps_ifd = {
           }
first_ifd = {piexif.ImageIFD.Make: u"Basler",
             piexif.ImageIFD.Software: u"Inveox"
             }

exif_dict = {"0th":zeroth_ifd, "Exif":exif_ifd, "GPS":gps_ifd, "1st":first_ifd, "thumbnail":thumbnail}
exif_bytes = piexif.dump(exif_dict)
piexif.insert(exif_bytes, "Image_Rot10.jpg")
im = Image.open("Image_Rot10.jpg")
im.thumbnail((100, 100), Image.ANTIALIAS)
im.save("out.jpg", exif=exif_bytes)

setImageMeta("Image_Rot10.jpg")`

How ever I get an error that 2

Traceback (most recent call last): File "C:\Users\eclipse-workspace\MetaData.py", line 70, in setImageMeta("Image_Rot10.jpg") File "C:\Users\eclipse-workspace\MetaData.py", line 65, in setImageMeta Inveox 2 (38000.0,) 5 exif_bytes = piexif.dump(exif_dict) File "C:\Users\AppData\Local\Programs\Python\Python35\lib\site-packages\piexif_dump.py", line 68, in dump exif_set = _dict_to_bytes(exif_ifd, "Exif", zeroth_length) File "C:\Users\AppData\Local\Programs\Python\Python35\lib\site-packages\piexif_dump.py", line 338, in _dict_to_bytes offset) File "C:\Users\AppData\Local\Programs\Python\Python35\lib\site-packages\piexif_dump.py", line 248, in _value_to_bytes

four_bytes_over = new_value

UnboundLocalError: local variable 'new_value' referenced before assignment

What am I doing wrong here? I have tried strings ratios and so on.......

[hMatoba]

http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf http://piexif.readthedocs.io/en/latest/appendices.html

[jcjumley]

having an error with: comment_string = 'Heading?' + str(hdg) + "_Sortie?" + str(sortie_number) + "_WindSpeed?TBD_WindDirection?TBD_UVindex?TBD_PixelSize?500" prints b'ASCII\x00\x00\x00Heading_Sortie_WindSpeed_WindDirection_UVindex_PixelSize' piexif.helper.UserComment.dump(comment_string,encoding='ascii') exif_dict["Exif"][piexif.ExifIFD.UserComment] = user_comment exif_bytes = piexif.dump(exif_dict) _UnboundLocalError: local variable 'new_value' referenced before assignment (dump.py, line 337 _dict_to_bytes)

[otakarkuchar]

Hello I try to set my FocalLength exif parameter using

 `def setImageMeta(image_path, make = u"Basler", model = u"acA2440-35um", focal_length = 4, sensor_width = 8.4, max_image_circle = "2/3\""):
    o = io.BytesIO()
    thumb_im = Image.open(image_path)
    width, height = thumb_im.size
    width = int(width *0.5)
    height = int(height * 0.5)
    thumb_im.thumbnail((width,height), Image.ANTIALIAS)
    thumb_im.save(o, "jpeg")
    thumbnail = o.getvalue()

zeroth_ifd = {piexif.ImageIFD.Make: u"Basler",
          piexif.ImageIFD.Software: u"Inveox"
          }
exif_ifd = {
            #piexif.ExifIFD.LensMake: "LensMake",
            piexif.ExifIFD.FocalLength: 8/1,
            }
gps_ifd = {
           }
first_ifd = {piexif.ImageIFD.Make: u"Basler",
             piexif.ImageIFD.Software: u"Inveox"
             }

exif_dict = {"0th":zeroth_ifd, "Exif":exif_ifd, "GPS":gps_ifd, "1st":first_ifd, "thumbnail":thumbnail}
exif_bytes = piexif.dump(exif_dict)
piexif.insert(exif_bytes, "Image_Rot10.jpg")
im = Image.open("Image_Rot10.jpg")
im.thumbnail((100, 100), Image.ANTIALIAS)
im.save("out.jpg", exif=exif_bytes)

setImageMeta("Image_Rot10.jpg")`

How ever I get an error that 2

Traceback (most recent call last): File "C:\Users\eclipse-workspace\MetaData.py", line 70, in setImageMeta("Image_Rot10.jpg") File "C:\Users\eclipse-workspace\MetaData.py", line 65, in setImageMeta Inveox 2 (38000.0,) 5 exif_bytes = piexif.dump(exif_dict) File "C:\Users\AppData\Local\Programs\Python\Python35\lib\site-packages\piexif_dump.py", line 68, in dump exif_set = _dict_to_bytes(exif_ifd, "Exif", zeroth_length) File "C:\Users\AppData\Local\Programs\Python\Python35\lib\site-packages\piexif_dump.py", line 338, in _dict_to_bytes offset) File "C:\Users\AppData\Local\Programs\Python\Python35\lib\site-packages\piexif_dump.py", line 248, in _value_to_bytes

four_bytes_over = new_value

UnboundLocalError: local variable 'new_value' referenced before assignment

What am I doing wrong here? I have tried strings ratios and so on.......

Did you solve problem? I have absolutly the same problem with focal length

[Dave-van-der-Meer]

I could set a focal length with the following code:

exif_dict = piexif.load(image_file_path)
exif_dict['Exif'][piexif.ExifIFD.FocalLength] = (3,1)

The issue that I have is,that I can only input integers, not floats.