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

[Marko Mäkelä]

On Sat, Feb 21, 2015 at 08:21:23PM +0100, David Bremner wrote:
>>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.
>
>This is most likely an upstream issue, so can you try darktable from 
>experimental to see if it has the same problem?

Indeed, both the coarse and fine focus buttons do work with my macro 
lens and darktable_1.6.2-1_amd64.deb.

But, the first time I tried it with 1.6.2, none of the focus buttons 
worked with my macro lens. I had to move the lens to AF mode and 
half-press the shutter button. Then, the focus controls from Darktable 
would start to have some effect (fighting against the AF of the camera).  
Finally, in MF mode, both the coarse and fine focus controls worked.

I shortly went back to 1.4.2-1+b3 (which refused to start, until I 
removed $HOME/.cache/darktable) and then reinstalled 1.6.2-1. There 
could be some missing initialization step that causes the focus controls 
occasionally not to work. Power-cycling the camera and restarting 
Darktable could help.

My zoom lens still does not work with Darktable 1.6.2. But, the focus 
point did move when I tested with the lens in MF mode, using gphoto2 --shell:

capture-preview
set-config /main/actions/manualfocusdrive 6
set-config /main/actions/manualfocusdrive 6
set-config /main/actions/manualfocusdrive 6
set-config /main/actions/manualfocusdrive 6
set-config /main/actions/manualfocusdrive 6
set-config /main/actions/manualfocusdrive 6
capture-preview

My first tests with Darktable (when the focus controls worked) were with 
Debian unstable at the end of April 2014. I found a sequence of images 
that I had shot on 2014-05-01 with the macro lens, successfully using 
the fine focus control buttons from the Darktable GUI.

I am not sure, but it could be that the focus controls did work even 
with the zoom lens (EF-S 18-135mm 1:3.5-5.6 IS STM) at that time.

	Marko