タイムスタンプとexifで2秒ほどのズレ
これ書き込みに2秒くらいかかってるてことかな?

$ TZ=ja_JP ls --full-time /media/matoken/8765-4321/DCIM/105_0821/IMGP5484.JPG
-rw-r--r-- 1 matoken matoken 11423704 2018-08-21 00:09:02.000000000 +0000 /media/matoken/8765-4321/DCIM/105_0821/IMGP5484.JPG
$ TZ=ja_JP exiftime /media/matoken/8765-4321/DCIM/105_0821/IMGP5484.JPG
Image Created: 2018:08:21 00:08:59
Image Generated: 2018:08:21 00:08:59
Image Digitized: 2018:08:21 00:08:59
$ TZ=ja_JP ls --full-time /media/matoken/8765-4321/DCIM/105_0821/IMGP5485.JPG
-rw-r--r-- 1 matoken matoken 11305392 2018-08-21 00:09:12.000000000 +0000 /media/matoken/8765-4321/DCIM/105_0821/IMGP5485.JPG
$ TZ=ja_JP exiftime /media/matoken/8765-4321/DCIM/105_0821/IMGP5485.JPG
Image Created: 2018:08:21 00:09:09
Image Generated: 2018:08:21 00:09:09
Image Digitized: 2018:08:21 00:09:09