ExifTool Forum

ExifTool => Archives => Topic started by: Archive on May 12, 2010, 08:53:57 AM

Title: Difference camera vs auto vs. base ISO
Post by: Archive on May 12, 2010, 08:53:57 AM
[Originally posted by linuxuser on 2006-11-09 18:12:25-08]

Can anyone please explain the makernotes of this picture: http://web.canon.jp/Imaging/psa710is/sample/IMG_0541.JPG

I get:
[MakerNotes]    0x0010 Camera ISO                      : 80
[MakerNotes]    0x0001 Auto ISO                        : 100
[MakerNotes]    0x0002 Base ISO                        : 79
[Composite]          - ISO                             : 80
Title: Re: Difference camera vs auto vs. base ISO
Post by: Archive on May 12, 2010, 08:53:57 AM
[Originally posted by exiftool on 2006-11-09 19:15:54-08]

Canon stores many forms of ISO information.  Basically, what you want
to use is the composite ISO value which should be accurate no matter
what mode your camera is in.

The CameraISO gives the camera setting, but this isn't available for
all models.

The BaseISO and AutoISO combine to give the ISO that was used for
taking the picture, with the formula ISO = BaseISO * AutoISO / 100.

I'm not sure why Canon does it this way, but I'm sure they have their reasons.

I hope this helps.

- Phil