Author Topic: Flash Compensation Data Display Issue  (Read 9082 times)

sidewinder

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Flash Compensation Data Display Issue
« on: January 23, 2010, 11:08:30 PM »
I have a strange one for you guys.

I saw Ian Goldstein's "Exposure and Flash Compensation" code replacement file and thought it was interesting. So I decided to test it out. I took some photos with both exposure and flash compensation modified and it worked perfectly. Here is the expression I used for the contact sheet:

{lens}mm @ ISO {iso} \comp{comp}\ Flash ({flash:0,2}) \comp{fcmp}\

Here is one result:

35mm @ ISO 200 +0.3 EV Flash(on) +0.7 EV

This matches the data in the EXIF.

Then, I open the image in Capture NX 2, change anything, and save it out. This is then displayed in the contact sheet:

35mm @ ISO 200 +0.3 EV Flash(on)

PM no longer shows any flash exposure compensation. The EXIF still shows the +0.7 flash exposure compensation in both PM and CNX. Why does PM still show the exposure compensation but not the flash exposure compensation?

By the way, I tried using this expression instead:

{lens}mm @ ISO {iso} {comp} Flash ({flash:0,2}) {fcmp}

I get this:

35mm @ ISO 200 +0.3 EV Flash(on) +0.0

Ideas???

This is on a Mac Pro (2008) running Mac OS X 10.6.2, Photo Mechanic 4.6.2.1, and Capture NX 2 2.2.4.

Scott
« Last Edit: January 26, 2010, 10:09:36 AM by sidewinder »

Offline Kirk Baker

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Re: Flash Compensation Data Dispaly Issue
« Reply #1 on: January 24, 2010, 07:03:26 AM »
Scott,

I have a strange one for you guys.

I saw Ian Goldstein's "Exposure and Flash Compensation" code replacement file and thought it was interesting. So I decided to test it out. I took some photos with both exposure and flash compensation modified and it worked perfectly. Here is the expression I used for the contact sheet:

{lens}mm @ ISO {iso} \comp{comp}\ Flash ({flash:0,2}) \comp{fcmp}\

Here is one result:

35mm @ ISO 200 +0.3 EV Flash(on) +0.7 EV

This matches the data in the EXIF.

Then, I open the image in Capture NX 2, change anything, and save it out. This is then displayed in the contact sheet:

35mm @ ISO 200 +0.3 EV Flash(on)

PM no longer shows any flash exposure compensation. The EXIF still shows the +0.7 flash exposure compensation in both PM and CNX. Why does PM still show the exposure compensation but not the flash exposure compensation?

By the way, I tried using this expression instead:

{lens}mm @ ISO {iso} {comp} Flash ({flash:0,2}) {fcmp}

I get this:

35mm @ ISO 200 +0.3 EV Flash(on) +0.0

Ideas???

This is on a Mac Pro (2008) running Mac OS X 10.6.2, Photo Mechanic 4.6.2.1, and Capture NX 2 2.2.4.

I don't actually know.  Capture NX2 is changing the file so I don't know if it has removed or perhaps moved some data around in such a way that PM doesn't see it anymore.  I'll have to ask Dennis Walker about this and get back to you.

-Kirk

sidewinder

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Re: Flash Compensation Data Dispaly Issue
« Reply #2 on: January 24, 2010, 10:38:57 AM »
Kirk,

I misspoke. I don't know how to see what PM thinks is in the EXIF flash exposure compensation field.

I used exiftool to create a text file with the EXIF data for both virgin and NX 2 modified files. I used grep (case insensitive) to find every line in each file with the word "flash" in it. Only one line was different.

The "good" virgin file had this:

Flash Exposure Compensation    : 0.0

While the "bad" NX 2 edited file had this:

Flash Exposure Compensation     : +2/3

Both had these three lines with "0.7" in them:

Supplemental Categories         : 1/30sec @ f/6.3 - 35mm using AF VR Zoom 16-85mm f/3.5-5.6G IF-ED, ISO: 200 - Exp Comp: +0.3 - Flash Comp: +0.7, Program: Aperture Priority - Focus Mode: AF-C - White Balance: AUTO
Flash Group A Exposure Comp     : +0.7
Flash Group B Exposure Comp     : +0.7

Does that help?

What EXIF field do you guys read to get the data for flash exposure compensation?

Scott
« Last Edit: January 24, 2010, 10:45:06 AM by sidewinder »

sidewinder

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Re: Flash Compensation Data Dispaly Issue
« Reply #3 on: January 25, 2010, 10:52:26 AM »
Kirk,

What EXIF field do you guys read to get the data for flash exposure compensation?

Scott

Offline Kirk Baker

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Re: Flash Compensation Data Dispaly Issue
« Reply #4 on: January 25, 2010, 02:46:40 PM »
Scott,

What EXIF field do you guys read to get the data for flash exposure compensation?

We get that data out of the Nikon Maker Note which is proprietary data and must be getting modified in some way by NX2 such that our parser no longer finds the flash exposure compensation data.

-Kirk

sidewinder

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Re: Flash Compensation Data Dispaly Issue
« Reply #5 on: January 25, 2010, 04:17:43 PM »
Do you know of any tools that read in and then present the Maker Note is readable form?

By the way, I did the test with the Flash Commander mode (Flash Group Control) off and the results were no different.

Do you want a copy of an image file that has been modified by Capture NX 2? Or do you have the software in-house to test with?

Scott
« Last Edit: January 25, 2010, 04:19:23 PM by sidewinder »

Offline Kirk Baker

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Re: Flash Compensation Data Dispaly Issue
« Reply #6 on: January 25, 2010, 06:50:01 PM »
Scott,

Do you know of any tools that read in and then present the Maker Note is readable form?

By the way, I did the test with the Flash Commander mode (Flash Group Control) off and the results were no different.

Do you want a copy of an image file that has been modified by Capture NX 2? Or do you have the software in-house to test with?

We have Capture NX2 already.

Thanks,

-Kirk

sidewinder

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Re: Flash Compensation Data Dispaly Issue
« Reply #7 on: January 25, 2010, 07:15:55 PM »
Well, let me know if you guys figure anything out.

Scott

sidewinder

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Re: Flash Compensation Data Display Issue
« Reply #8 on: January 27, 2010, 09:42:35 PM »
Do you know of any tools that read in and then present the Maker Note is readable form?

Scott

Offline Kirk Baker

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Re: Flash Compensation Data Display Issue
« Reply #9 on: January 27, 2010, 09:47:35 PM »
Scott,

Do you know of any tools that read in and then present the Maker Note is readable form?

I'm not quite sure what you're asking, but ExifTool extracts more information from an image file than any other utility I have come across.

-Kirk

sidewinder

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Re: Flash Compensation Data Display Issue
« Reply #10 on: January 27, 2010, 10:10:55 PM »
It wasn't a hard to understand question.

The MakersNotes are binary data. So the flash exposure compensation data is difficult to locate. I wanted to know if there was a tool that could interpret at least some of the MakersNotes data without mne having to try and figure out the location through laborious testing.

Based on your response, however, I guess not....

Scott


sidewinder

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Re: Flash Compensation Data Display Issue
« Reply #11 on: January 29, 2010, 03:05:34 PM »
Kirk,

Any update on this issue?

Scott

Offline Kirk Baker

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Re: Flash Compensation Data Display Issue
« Reply #12 on: January 29, 2010, 03:24:42 PM »
Scott,

It wasn't a hard to understand question.

The MakersNotes are binary data. So the flash exposure compensation data is difficult to locate. I wanted to know if there was a tool that could interpret at least some of the MakersNotes data without mne having to try and figure out the location through laborious testing.

Based on your response, however, I guess not....

I did suggest ExifTool.  Have you tried that?

-Kirk

sidewinder

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Re: Flash Compensation Data Display Issue
« Reply #13 on: January 29, 2010, 03:35:31 PM »
Kirk,

I know. That will show the binary data that makes up the "MakersNotes". But, it doesn't decode it. Which is why I asked if you knew of a tool that did.

Anyway, it doesn't really matter. My last post was asking if you have looked into the problem any further. Have you?

Scott

Offline Kirk Baker

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Re: Flash Compensation Data Display Issue
« Reply #14 on: January 29, 2010, 05:59:40 PM »
Scott,

I know. That will show the binary data that makes up the "MakersNotes". But, it doesn't decode it. Which is why I asked if you knew of a tool that did.

Anyway, it doesn't really matter. My last post was asking if you have looked into the problem any further. Have you?

No.  We're concentrating on fixing issues in Photo Mechanic that either cause crashes, hangs, or performance problems.

-Kirk