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Northrup Image Standard

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jflu:
The following is an EXIF Tool config file to produce Tony Northrup's idea of an image setting standard: Its an interesting idea so I thought it was worth playing with.
Essentially we translate the current parameters like lens focal length, F-Stop, ShutterSpeed, ISO, which mean very different things depending on the camera; to settings that would be equal on all cameras.

Those are 

* V (View Angle)  -  Field of view, fortunately EXIFtool calculates this for us!
* D (Duration)  -  This is the shutter speed * 1000 and is how long we capture for in milliseconds versus fractions of a second
* A (Aperture)  -  This is a bit more complicated ( 500 /( ((FSTOP * CROPFactor) / sqrt(2) ) ^2 ))
* L (Luminescence)  -  ISO*(CROPFactor^2))/10

I have also included an optional bat file (windows) that will first display the results and then if you hit enter add the Northrup settings to the UserComment of an image.

to use the config without any other configs simply rename it to ".ExifTool_config" place it in the same directory as your exiftool.exe program and rename the     exiftool.exe    to   exiftool(-NorthrupSC -Northrup35 -NorthrupAuto -PrintSize -k).exe

the output should look something like:

--- Code: ---Field Of View                   : 39.5 deg
Shutter Speed                   : 1/320
Aperture                        : 3.2
ISO                             : 100
Scale Factor To 35 mm Equivalent: 1.0
Focal Length                    : 50.0 mm
Northrup 35                     : V39.5-50.0 mm D3.13 A98 L10
Northrup Auto                   : V39.5-50.0 mm D3.13 A97 L10
Native Image Size               : 26.0 x 17.3 inches @ 240 dpi
Physical Image Size B           : 31.2 x 20.8 in @ 200 dpi
--- End code ---

Otherwise the bat file specifies the config file to use.

The config file has some other extras like the native print size and the print size at 200 dpi.
Northrup 35 assumes you have a 35mm sensor and the crop factor is 1
Northrup Auto uses the ScaleFactor35efl  tag to determine the crop factor.

The bat file is set to write the NorthrupAuto results.


Tony Northrup's video is called "Camera settings are outdated. Here's a better way. WARNING: NERDY" for reference.

jflu:
One potential issue is when images have been resized the Scale Factor To 35 mm Equivalent  number produced by the ScaleFactor35efl tag changes as does the FOV calculation. Presumably this is because it sees the resize as a crop, and if it were a post-crop then the change would be correct.

Here is an example image where the Northrup settings pre-resize.


--- Code: ---Field Of View                   : 39.5 deg
Shutter Speed                   : 1/125
Aperture                        : 4.5
ISO                             : 100
Scale Factor To 35 mm Equivalent: 1.0
Focal Length                    : 50.0 mm
Northrup 35                     : V39.5-50.0 mm D8.00 A49 L10
Northrup Auto                   : V39.5-50.0 mm D8.00 A49 L10
Native Image Size               : 26.0 x 17.3 inches @ 240 dpi
Physical Image Size B           : 31.2 x 20.8 in @ 200 dpi

--- End code ---

and post resize to 30% of the original image

--- Code: ---Field Of View                   : 12.3 deg
Shutter Speed                   : 1/125
Aperture                        : 4.5
ISO                             : 100
Scale Factor To 35 mm Equivalent: 3.3
Focal Length                    : 50.0 mm
Northrup 35                     : V12.3-50.0 mm D8.00 A49 L10
Northrup Auto                   : V12.3-50.0 mm D8.00 A4 L111
Native Image Size               : 7.8 x 5.2 inches @ 240 dpi
Physical Image Size B           : 9.4 x 6.2 in @ 200 dpi
--- End code ---

I think this is ok because in principal this tool would be used on original full resolution images. It also means if you post-crop you can see how that effectively has a similar impact as a smaller sensor.

Phil Harvey:
Interesting.  I'll have to read this in more detail if I get a chance.

Just one quick point: Your config file seems to have a stray ValueConv at the end that isn't used for anything.

- Phil

jflu:
Oh Interesting so that function exist in EXIFtool then I presume. I am a completely new user of EXIFtool and perl actually; but its really an amazing tool!

I appreciate that it was free to download and use; I am planning to play with the perl library version next.

jflu:
Updated config without the unnecessary ValueConv function.

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