Thanks for the report, I'll try to investigate this today.

I just checked while camera in Bulb mode and I took the lowest capture possible for 600D (0.00025 seconds which is 1/4000). I used exiftool to check the CR2 and got this:
Appears everything is fine. I tested for different exposures and not a single issue.

I can not even set these short exposure times.

In the camera settings I get the log message:
2018-06-28T11:12:02: [ERROR] Requested exposure value (0.00025) seconds out of bounds [0.001,3600].

and in the capture window, it is limited to 3 digits after the comma. 0,0001 would be the shortest I can set.

Two informations: I am on a Mac with local settings set to German. We use "," as the decimal separator. It seems the localization is not consistent in capture window and the camera settings as the camera settings use "." and the caption module uses ",".

Enable logging and attach it here after you connect and try to capture.

Ok, now the device driver crashed reproducibly.

What I did:

Starting Indi
On main control of the DSLR trying to set exposure to 0.00025 -> error message
Then setting to 0.001. Hitting enter
Photo is taken, driver crahes

Attached is the log

I took 4 pictures.

I selected exposure 0,001 (the lowest available in the GUI), added it to the sequence queue, activated. The picture was taken (CR2). The result in Exiftool is this:

Image Size : 5616x3744
Lens : 17.0 - 40.0 mm
Lens ID : Canon EF 17-40mm f/4L USM
Megapixels : 21.0
Preview Image : (Binary data 961395 bytes, use -b option to extract)
Scale Factor To 35 mm Equivalent: 1.0
Shooting Mode : Bulb
Shutter Speed : 1


So Exiftools tells me this was a 1s exposure (which is wrong, I heard it was much shorter than this). What's particularly irritating is the fact that the value in the exposure field changed to 0,010 all by itself after the picture had been taken.

I then took photos of 0,500s (CR2), 0,010s (CR2), and one last photo at 0,010s (FITS).

Exiftool tells me they all were 1s photos. They all look the same. It appears the exposure time has been the same in all 4 pictures. But it was not 1s as exiftool said.

[2018-06-28T14:04:15.980 CEST DEBG ][ org.kde.kstars.indi] - Canon DSLR EOS 5D Mark II : "[DEBUG] Finding optimal exposure setting for 0.050001 seconds in shutterspeed (count=1)... "
[2018-06-28T14:04:15.980 CEST DEBG ][ org.kde.kstars.indi] - Canon DSLR EOS 5D Mark II : "[DEBUG] Best match: -1 seconds Index: 0 "

I think this is where things go wrong...

I should add that after taking the 0,500s photo the value in the exposure field changed to 0,050 by itself (just like it changed to 0,010 after taking the 0,001s photo).

To make this even more confusing:

I had a look at the FITS images I took in parallel to the CR2s. There the exposure time listed is correct and matches the file name, however it was never really used. All images from 1/20 to 1/2 second look exactly the same.

The log file is oddly missing some key information... let me investigate that more since it's not the first time.

Yes, I believe having exposure times right is an absolute necessity. I'm ready to run as many tests as needed to hunt this bug down. Just le me know what I can do.

Under Options ---> Debug Levels, make sure "Driver Debug" is checked and then click "Save" in configuration. Then restart KStars and try to connect again, I think this is the problem of the complete debug log not showing up.