[Pkg-phototools-devel] Bug#778916: darktable: manual focus only works in big steps on Canon EF-S 60mm 1:2.8 USM macro

[Marko Mäkelä]

Package: darktable
Version: 1.4.2-1+b3
Severity: normal

Dear Maintainer,

I am trying to use Darktable with a Canon EOS 650D in tethered mode.  
When I enable the live viewfinder, I would expect the focus buttons to 
affect the picture.

I tested this with two lenses today.

EF-S 18-135 IS STM: When the lens is in MF mode, the buttons do not seem 
to have any effect. In AF mode, the focus buttons sometimes affect the 
image, but the autofocus algorithm of the camera interferes, trying to 
focus where it wants. Most of the time, the focus buttons seem to have 
no effect on the live viewfinder image.

EF-S 60 IS USM 2.8: When the lens is in AF mode, the camera is playing 
its tricks as noted above. However, in MF mode, the coarse focus buttons 
do have the desired effect, and the fine focus buttons have no effect.  
I am sure that both the coarse and the fine focus buttons worked on this 
lens the first time when I tested Darktable, about 4 or 6 months ago.

To diagnose the problem, I tested gphoto2 --shell and the following commands:
capture-preview
get-config /main/actions/manualfocusdrive
set-config /main/actions/manualfocusdrive 6
...

The get-config command returns the following:

Label: Drive Canon DSLR Manual focus
Type: RADIO
Current: None
Choice: 0 Near 1
Choice: 1 Near 2
Choice: 2 Near 3
Choice: 3 None
Choice: 4 Far 1
Choice: 5 Far 2
Choice: 6 Far 3

I tried set-config using the values 0 through 6. Values 0,3,4 had no
noticeable effect. With the values 2 and 6, the focus moved in bigger
steps and with 1 and 5, in smaller steps (as observed by looking through
the indicator window on the lens barrel).

So, I suspect that the mapping of the fine-focus buttons was changed
from "Near 2" and "Far 2" to "Near 1" and "Far 1", which have no effect
on my EOS 650D and EF-S 60 IS USM 2.8.

If there is a configuration option to remap the focus buttons to the
values supported by libgphoto2, then it seems to be well hidden from
a newbie like me. For example, right-clicking the focus buttons does not
pop up any menu, and the tooltip text (when hovering the mouse pointer
over the buttons) only describes basic usage.
-- System Information:
Debian Release: 8.0
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=fi_FI.utf8, LC_CTYPE=fi_FI.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages darktable depends on:
ii  gtk2-engines              1:2.20.2-3
ii  libatk1.0-0               2.14.0-1
ii  libc6                     2.19-15
ii  libcairo2                 1.14.0-2.1
ii  libcolord2                1.2.1-1+b2
ii  libcurl3-gnutls           7.38.0-4
ii  libexiv2-13               0.24-4.1
ii  libflickcurl0             1.25-3
ii  libgcc1                   1:4.9.2-10
ii  libgdk-pixbuf2.0-0        2.31.1-2+b1
ii  libgl1-mesa-glx [libgl1]  10.4.2-2
ii  libglib2.0-0              2.42.1-1
ii  libglu1-mesa [libglu1]    9.0.0-2
ii  libgnome-keyring0         3.12.0-1+b1
ii  libgomp1                  4.9.2-10
ii  libgphoto2-6              2.5.4-1.1+b2
ii  libgphoto2-port10         2.5.4-1.1+b2
ii  libgtk2.0-0               2.24.25-1
ii  libice6                   2:1.0.9-1+b1
ii  libilmbase6               1.0.1-6.1
ii  libjpeg62-turbo           1:1.3.1-11
ii  libjs-prototype           1.7.1-3
ii  libjs-scriptaculous       1.9.0-2
ii  libjson-glib-1.0-0        1.0.2-1
ii  liblcms2-2                2.6-3+b3
ii  liblensfun0               0.2.8-2
ii  liblua5.2-0               5.2.3-1.1
ii  libopenexr6               1.6.1-8
ii  libpango-1.0-0            1.36.8-3
ii  libpangocairo-1.0-0       1.36.8-3
ii  libpng12-0                1.2.50-2+b2
ii  librsvg2-2                2.40.5-1
ii  libsdl1.2debian           1.2.15-10+b1
ii  libsm6                    2:1.2.2-1+b1
ii  libsoup2.4-1              2.48.0-1
ii  libsqlite3-0              3.8.7.4-1
ii  libstdc++6                4.9.2-10
ii  libtiff5                  4.0.3-12
ii  libx11-6                  2:1.6.2-3
ii  libxext6                  2:1.3.3-1
ii  libxml2                   2.9.2+dfsg1-3
ii  zlib1g                    1:1.2.8.dfsg-2+b1

darktable recommends no packages.

darktable suggests no packages.

-- no debconf information