Nil pointer returned for [exifData tagValue:]

Question

I am trying to read EXIF ​​data from photos taken using apple camera application containing EXIF ​​information. I am using the iphone-exif library, available at http://code.google.com/p/iphone-exif/ .

My problem is that I get tag information using the function [exifData tagDefinition:]:

EXFTag* tag = [exifData tagDefinition:[NSNumber numberWithInt:EXIF_ExposureTime]];

Tag information is correctly displayed in the console:

tag name: ExposureTime
tag dataType: 5
tag ID: 33434
tags: 1
Tag address: 0x15f900

but I can not get the tag value:

id value = [exifData tagValue: [NSNumber numberWithInt:EXIF_ExposureTime]];

I get a null pointer:

value: 0x0 value size: 4 value: 0

Results match other tag identifiers such as ISO Speed ​​or Focal Length.

- ? ?

Answer 1

UIImagePickerController, exif. .

: UIImagePickerController EXIF-

Answer 2

. mracoker, UIImagePickerController , EXIF ​​ . ...: '(