diff --git a/wp-admin/includes/image.php b/wp-admin/includes/image.php
index 6ea4edecea..3591231787 100644
--- a/wp-admin/includes/image.php
+++ b/wp-admin/includes/image.php
@@ -254,13 +254,13 @@ function wp_read_image_metadata( $file ) {
 		if ( ! empty($exif['DateTimeDigitized'] ) )
 			$meta['created_timestamp'] = wp_exif_date2ts($exif['DateTimeDigitized'] );
 		if ( ! empty($exif['FocalLength'] ) )
-			$meta['focal_length'] = wp_exif_frac2dec( $exif['FocalLength'] );
+			$meta['focal_length'] = (string) wp_exif_frac2dec( $exif['FocalLength'] );
 		if ( ! empty($exif['ISOSpeedRatings'] ) ) {
 			$meta['iso'] = is_array( $exif['ISOSpeedRatings'] ) ? reset( $exif['ISOSpeedRatings'] ) : $exif['ISOSpeedRatings'];
 			$meta['iso'] = trim( $meta['iso'] );
 		}
 		if ( ! empty($exif['ExposureTime'] ) )
-			$meta['shutter_speed'] = wp_exif_frac2dec( $exif['ExposureTime'] );
+			$meta['shutter_speed'] = (string) wp_exif_frac2dec( $exif['ExposureTime'] );
 	}
 
 	foreach ( array( 'title', 'caption', 'credit', 'copyright', 'camera', 'iso' ) as $key ) {