Canon 1D wrong CoC

[alain.p]

Hello,

First of all thanks for this wonderful tool and for the dynamism in the upgrades.

I tried several version of exiftool (8.27, 9.35 and 9.41) and all gave me the same (wrong)
result for the "Circle of Confusion" and the "Scale Factor To 35mm" for my Canon 1D Mk iv.
The value I got was resp. 0.027 and 1.1 instead of 0.025 (according DoF Master) and 1.3
(according Canon spec.); therefore the values computed based on these parameters are
also wrong (i.e. 35mm equivalent focal length, near & far focus distances).

Could you change that in a near futur?

Thanks.
Alain

Short abstract:

Code Select Expand


ExifTool Version Number         : 9.41
File Name                       : 1D4_6582.JPG
Directory                       : .
File Size                       : 9.2 MB
File Modification Date/Time     : 2013:11:24 14:36:50+01:00
File Access Date/Time           : 2013:11:25 10:24:56+01:00
File Creation Date/Time         : 2013:11:25 10:24:56+01:00
File Permissions                : rw-rw-rw-
File Type                       : JPEG
MIME Type                       : image/jpeg
Exif Byte Order                 : Little-endian (Intel, II)
Make                            : Canon
Camera Model Name               : Canon EOS-1D Mark IV
Canon Exposure Mode             : Aperture-priority AE
Lens Type                       : Canon EF 70-200mm f/2.8L IS + 2x
Max Focal Length                : 400 mm
Min Focal Length                : 140 mm
Focal Units                     : 1/mm
Max Aperture                    : 5.7
Min Aperture                    : 64
Camera Type                     : EOS High-end
Canon Image Type                : Canon EOS-1D Mark IV
Canon Firmware Version          : Firmware Version 1.1.3
Image Size                      : 4896x3264
Lens                            : 140.0 - 400.0 mm
Lens ID                         : Canon EF 70-200mm f/2.8L IS + 2x
Red Eye Reduction               : Off
Scale Factor To 35 mm Equivalent: 1.1
Circle Of Confusion             : 0.027 mm
Field Of View                   : 4.7 deg
Focal Length                    : 400.0 mm (35 mm equivalent: 443.2 mm)
Hyperfocal Distance             : 737.61 m
Lens                            : 140.0 - 400.0 mm (35 mm equivalent: 155.1 - 443.2 mm)


[Phil Harvey]

Hi Alain,

Canon is known for storing incorrect focal plane resolution values for some models.  I suspect that this is the problem here.  But good luck submitting a bug report to Canon.

If you come back and tell me "but DoF Master gives the correct value", then all I can say is they have a stored a lookup table for all Canon models -- a prospect that I want to avoid for a number of reasons.

- Phil

[alain.p]

Hi Phil,

I'm sorry I didn't find the post you pointed out during my search.
And honestly I was thinking these values were got out of a lookup table and not computed
from the focal plane resolution.

Anyway I understand you can't do anything to correct this problem; only Canon could.

Thanks for your wonderful tool.

Alain