hjs@ubuntu:~$ gphoto2 --capture-image-and-download
*** Error ***
Canon EOS Capture failed to release: Perhaps no focus?
ERROR: Could not capture image.
ERROR: Could not capture.
hjs@ubuntu:~$ gphoto2 --capture-image
*** Error ***
Canon EOS Capture failed to release: Perhaps no focus?
ERROR: Could not capture image.
ERROR: Could not capture.
切换成manual focus，则ok。不知道为什么
hjs@ubuntu:~$ gphoto2 --capture-image
New file is in location /capt0000.jpg on the camera
---capture-- 0 2015-04-08 14:30:21
New file is in location /capt0000.jpg on the camera
---capture-- 1 2015-04-08 14:30:26
New file is in location /capt0000.jpg on the camera
---capture-- 2 2015-04-08 14:30:32
New file is in location /capt0000.jpg on the camera
---capture-- 3 2015-04-08 14:30:38
New file is in location /capt0000.jpg on the camera
---capture-- 0 2015-04-08 14:39:36
Deleting ‘capt0000.jpg‘ from folder ‘/‘...
New file is in location /capt0000.jpg on the camera
Saving file as temp0.jpg
Deleting file /capt0000.jpg on the camera
---extract file name temp0.jpg
---capture-- 1 2015-04-08 14:39:40
Deleting ‘capt0000.jpg‘ from folder ‘/‘...
New file is in location /capt0000.jpg on the camera
Saving file as temp1.jpg
Deleting file /capt0000.jpg on the camera
---extract file name temp1.jpg
---capture-- 2 2015-04-08 14:39:44
Deleting ‘capt0000.jpg‘ from folder ‘/‘...
New file is in location /capt0000.jpg on the camera
Saving file as temp2.jpg
Deleting file /capt0000.jpg on the camera
---extract file name temp2.jpg
---capture-- 3 2015-04-08 14:39:48
Deleting ‘capt0000.jpg‘ from folder ‘/‘...
New file is in location /capt0000.jpg on the camera
Saving file as temp3.jpg
Deleting file /capt0000.jpg on the camera
---extract file name temp3.jpg
---capture-- 4 2015-04-08 14:39:52
Deleting ‘capt0000.jpg‘ from folder ‘/‘...
New file is in location /capt0000.jpg on the camera
Saving file as temp4.jpg
Deleting file /capt0000.jpg on the camera
原文：http://www.cnblogs.com/cutepig/p/4404139.html