Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Sony Alpha dSLR / Konica Minolta dSLR, Sony SLT

Reply
 
Thread Tools Search this Thread
Old Jun 4, 2009, 5:23 PM   #1
Senior Member
 
Tullio's Avatar
 
Join Date: Jan 2006
Posts: 7,370
Default EXIF data from A200

This topic may apply to probably most (if not all) of the Sony A models. I've posted a similar thread way back but perhaps things have changed since and this time someone might provide me/us with some good info.

I've been trying to fine tune my A200 in terms of Contrast, Saturation and Sharpness under different modes (Standard, Landscape, Portrait, etc..). The problem is that I can not use the EXIF data for comparison purposes because Sony does not provide enough information. For instance, for each of this adjustments, there are a total of 7 levels (from -3 to +3). However, just about every EXIF reader program I came across will simply show LOW/SOFT, NNORMAL or HIGH/HARD. We know that NORMAL=0 but LOW/SOFT could be -1, -2 or -3. The same with HIGH/HARD on the plus side. The most comprehensive EXIF program I've used is EXIFTool and the GUI interface that can be used in combination with exiftool allows you to see the exif data as numbers. That works wonderfully with Olympus cameras as you can see the internal (factory preset) values as well as the values you set in the camera. But, when it comes to the Sony EXIF data, the program does not work. If you set any of the options to a negative value, the program reports as 1. Any positive value it reports as 2. So, if I set Contrast to -2, Saturation to +1 and Sharpness to +3, the exif program reports those values as 1 2 2. Absolutely useless.

My question is, does any one know of any s/w that can extract the EXIF data from Sony DSLRs in a meaningful way or I just have to go back to the 1970's and write down the settings for each shot so I can then compare the images and see the correct settings used in each one?
__________________

Tullio
Tullio is offline   Reply With Quote
Sponsored Links
Old Jun 4, 2009, 6:01 PM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

We discussed this briefly in a thread a while back here:

http://forums.steves-digicams.com/so...are-flaws.html

The maker notes section of the metadata containing that information is proprietary (unpublished by the camera manufacturers).

So, developers have to reverse engineer it to interpret it. To figure it out, you can take photos of a color chart using a various settings, and see what's changing in the metadata section of the image file being stored by the camera.

For example, take photos with contrast set to normal, +1, +2, etc. without any other settings changes. Then, look at the metadata to figure out what values are changing along with your settings changes and how they impact the image (and where their byte offsets are in the metadata). Much of this information has already been interpreted and published for some camera models. For example, here's a link to some of what ExifTool has figured out for Sony files:

http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/Sony.html

In the open source world, there are some libraries around that can handle some of that interpretation (and these libraries are used by software like digiKam )

For example, if you look at this blog page from a developer, he was looking for files from Sony dSLR models to work with for updating the Exiv2 library . It looks like he has much of it figured out already (based on how KM set parameters), and just needed some new files to figure out byte offset changes.

http://www.digikam.org/drupal/node/446

Of course, I volunteered to send some files, too (my entry is the one from JimC at the bottom of the page). lol
JimC is offline   Reply With Quote
Old Jun 5, 2009, 2:13 PM   #3
Senior Member
 
Tullio's Avatar
 
Join Date: Jan 2006
Posts: 7,370
Default

Thanks for all the info., Jim. Yes, as I mentioned, I've asked this question before. I was hoping something new had come up but I guess not. I wish I had the time to reverse-engineer the EXIF data from the A200. Perhaps during the summer months.
__________________

Tullio
Tullio is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 11:10 AM.