Canon 5D mkII: ISO, shutter speed, aperture values for auto settings

[JohnnyT]

Hi,

Can anyone tell me if the ISO, shutter speed, and aperture values that would be set if the camera were in fully-automatic mode are available in the metadata of the .CR2 file? I've looked through the Canon Tags page (http://www.exiftool.org/TagNames/Canon.html) and through the exiftool output. exiftool gives values for the following tags for an example .CR2 file I am using:

ISO
Auto ISO
Base ISO

Shutter Speed Value
Shutter Speed

Aperture Value
Aperture
Target Aperture           

I'm guessing Auto ISO is the ISO that would be active in fully-automatic mode? What about shutter speed and aperture?

Best regards

[BogdanH]

Hi,

I don't have this camera, but I believe metadata tags meanings are equal to camera I have (and other EOS cameras).

As far I could examine ISO, Auto ISO and Base ISO: no, these values don't give a hint for what camera would pick if in fully automatic mode. Try to take a photo in P-mode at ISO100 in dark condition. You will see, that all three ISO tags will have value 100 -in Auto mode, camera would probably pick much higher ISO value in such light condition.

Similar with various Shutter/Aperture tags: IMO, if values differ there, then that's because of camera's "internal calculations" and have nothing common with "if being in Auto mode" -but I could be wrong on this (so tryout).

Bogdan

[JohnnyT]

Hi Bogdan,

I don't actually have the 5D camera (or any EOS) either. Currently I am just interested in the statistics of auto vs manual settings. I have extracted 25,000 metadata files from a friend's collection of professional photographs.

I looked at more data today and saw that all pictures have an Auto ISO of 100, so that is useless. What is interesting though is that Base ISO is always equal to or less than ISO. Could ISO be the auto setting and Base ISO be the custom setting, or the other way around?

[BogdanH]

According to my observation, I believe, that:

AutoISO
-is the lowest ISO possible on EOS camera (which doesn't necessary apply for Canon p&s cameras).
BaseISO
-is actual (photo taken at) ISO value and is normally the same as selected ISO. In case selected ISO is not standard value (200, 400, 800,..) but some inbetween value was used instead (i.e. ISO600), then BaseISO may differ a bit from selected ISO. That is, if selected ISO is 600, then BaseISO may contain 617 instead.

Bogdan