×

INDI Library v2.0.7 is Released (01 Apr 2024)

Bi-monthly release with minor bug fixes and improvements

Read More...

Tempereature in DSLR subs?

  • Posts: 643
  • Thank you received: 62

Tempereature in DSLR subs? was created by Magnus Larsson

Hi!

I'm curious about the temperature data in DSLR subs. When I download subs from my Canon 1000D, there is a FITS keyword CCD-temp, filled in with a temperature. WHen I download CR2-files, the raw files, I cannot find any information about temperature in the EXIF-tags of the images.

So where does the FITS-keyword information on temperature come from? My belief was that the fits-files were converted form the cr2-files - and if the cr2-files do not contain information about temperature, where then does it come from? Or do the CR2-files contain this information, but I just cannot find it?

Magnus
5 years 3 months ago #33566

Please Log in or Create an account to join the conversation.

  • Posts: 111
  • Thank you received: 41

Replied by Thomas Stibor on topic Tempereature in DSLR subs?

Hi Magnus,

the (sensor) temperature is embedded in the raw DSLR format. Try e.g.
>exiftool IMG_8327.CR2 | grep Tem
Camera Temperature              : 28 C
Color Temperature               : 5200
Color Temp As Shot              : 5200
Color Temp Auto                 : 5200
Color Temp Measured             : 5200
Color Temp Daylight             : 5200
Color Temp Shade                : 7000
Color Temp Cloudy               : 6000
Color Temp Tungsten             : 3200
Color Temp Fluorescent          : 3720
Color Temp Kelvin               : 5200
Color Temp Flash                : 6277

The gphoto2 driver uses LibRaw to unpack the raw DSLR and uses exactly these EXIF information to read out the temperatures:
if (lib_raw.imgdata.other.SensorTemperature > -273.15f)
                gphoto->last_sensor_temp = lib_raw.imgdata.other.SensorTemperature;
            else if (lib_raw.imgdata.other.CameraTemperature > -273.15f)
                gphoto->last_sensor_temp = lib_raw.imgdata.other.CameraTemperature;
The following user(s) said Thank You: Magnus Larsson
5 years 3 months ago #33568

Please Log in or Create an account to join the conversation.

  • Posts: 643
  • Thank you received: 62

Replied by Magnus Larsson on topic Tempereature in DSLR subs?

Ah, wow, great!! Thanks!

Magnus
5 years 3 months ago #33569

Please Log in or Create an account to join the conversation.

Time to create page: 0.241 seconds