Wrong Scale Factor To 35 mm Equivalent for canon 5D mark iv

[KMagnusLarsson]

Dear ExifTool Forum

I get Scale Factor To 35 mm Equivalent: 1.2, for a Canon 5D mark iv RAW file. I would expect this to be 1.0 or close to 1.0.

Steps to repeat:
1) I take a raw format picture. Quality is set to "RAW" 6720x4480 pixels. File: https://filebin.net/f5dag7d4nqrbpdss/_Y8A4015.CR2
2) I transfer the raw file to computer an run "exiftool _Y8A4015.CR2". The file is not cropped or changed in any ways.
3) I get:
... snip ...
Image Size                      : 6720x4480
Lens                            : 135.0 mm
Lens ID                         : Canon EF 135mm f/2L
Megapixels                      : 30.1
Preview Image                   : (Binary data 2927411 bytes, use -b option to extract)
Scale Factor To 35 mm Equivalent: 1.2
... snip ...

The sensor size is 36.0 x 24.0m mm. The camera offers several formats and sizes of RAW and JPEG. My intention was to select the complete version with all RAW data. As far as I can see the picture is not cropped and a full 6720x4480 is recorded in the sample given by the link above. I would expect this to be 1.0 or close to 1.0.

exiftool -ver:
10.59

Installed from:
https://exiftool.org/index.html Mac OS X Package: ExifTool-10.59.dmg

osx 10.12.6

uname -a
Darwin 16.7.0 Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64 x86_64

Best regards,

Magnus Larsson

[Phil Harvey]

Hi Magnus,

I think you have to complain to Canon on this one:

Code Select Expand

> exiftool ../pics/CanonEOS5D_MarkIV.cr2 -focalplane"*" -sensorwidth -sensorheight
Focal Plane X Resolution        : 5719.148936
Focal Plane Y Resolution        : 5728.900256
Focal Plane Resolution Unit     : inches
Sensor Width                    : 6880
Sensor Height                   : 4544

If you crunch the numbers, this gives a sensor size of 20x30 mm, which is a crop factor of 1.2 (based on the 35 mm size of 24x36 mm).

My guess is that they are writing incorrect focal plane resolution values for this model.

- Phil

[KMagnusLarsson]

Hello Phil Harvey,

OK, thank you for checking.

Magnus

[KMagnusLarsson]

I have sent a trouble report to Canon Sweden.

I will forward feedback, if and when available.

Magnus

[Phil Harvey]

Apparently this problem also affects the 6D Mark II

- Phil