Go Back   Steve's Digicams Forums > Digicam Help > Newbie Help

Reply
 
Thread Tools Search this Thread
Old Dec 20, 2005, 8:04 PM   #1
Junior Member
 
Join Date: Dec 2005
Posts: 4
Default

I have some general questions about exif data. I'm just now getting into the photography scene, and while I'm not wanting to go pro or anything like that, I've been reading up on how cameras work, and how to properly adjust all the settings. I understand the exif data gives detail on settings used for any particular picture, but here are a couple of questions:

1.) How does one view exif data?

2.) Is exif data automatically attached to all pictures, or is it dependant on the camera?

3.) Can exif data be changed or added to after the picture is on your hdd?

Thanks for any info you can give to clear up this exif data stuff!
blurredvision is offline   Reply With Quote
Sponsored Links
Old Dec 20, 2005, 8:47 PM   #2
Senior Member
 
BillDrew's Avatar
 
Join Date: Jun 2002
Location: Hay River Township, WI
Posts: 2,512
Default

blurredvision wrote:
Quote:
1.) How does one view exif data?
Use an EXIF viewer. Most often one comes with the camera and very often there are better freeware ones available.
Quote:
2.) Is exif data automatically attached to all pictures, or is it dependant on the camera?
A BarbieCam might not put the EXIF data into the header of the JPEG file, but I think pretty much all digicams better than that do.
Quote:
3.) Can exif data be changed or added to after the picture is on your hdd?
There is software available to do that, but why would you want to?
BillDrew is offline   Reply With Quote
Old Dec 20, 2005, 10:31 PM   #3
Member
 
Join Date: Oct 2005
Posts: 55
Default

Opanda is good for exif viewing and it has a free download. It really helped me when I was looking for a camera I wanted to know the ISOs and camera model without having to ask. It works for online images as well...well mostly anyway. I have noticed that the exif info disapears sometimes when you edit the image.

http://www.opanda.com/en/download/index.html

After you install Opanda all you do is right click then choose to view exif data.
mnosbor is offline   Reply With Quote
Old Dec 20, 2005, 10:32 PM   #4
Member
 
Join Date: Mar 2005
Posts: 48
Default

If you are using windows XP, you can right click on the photo to get the exif info. Also you can add tittle to your photo.
KEV61 is offline   Reply With Quote
Old Dec 21, 2005, 9:40 AM   #5
Senior Member
 
Join Date: Sep 2005
Posts: 1,093
Default

My favorite exif viewer is Exifer, which is freeware. You can download it from the author's homepage: http://www.exifer.friedemann.info/. It makes a very nice thumbnail viewer in general for your image directories.

One thing I think bears special note: some programs remove the exif data from the file. This seems to be a preferred tactic of noise reduction programs to make the unregistered versions less desireable than the registered ones. So, if you're using the free version of noise reduction software, plan for it to clobber your exif info. Other image processing software may take a similar approach. In any case, it is always good practice to save your original image unmodified. Make a new copy for whatever mods you do to the original.


tclune is offline   Reply With Quote
Old Dec 21, 2005, 1:16 PM   #6
E.T
Senior Member
 
E.T's Avatar
 
Join Date: Jul 2003
Posts: 921
Default

tclune wrote:
Quote:
One thing I think bears special note: some programs remove the exif data from the file. This seems to be a preferred tactic of noise reduction programs to make the unregistered versions less desireable than the registered ones. So, if you're using the free version of noise reduction software, plan for it to clobber your exif info.
Which means backup EXIF (and IPTC) data with Exifer and put it back to image after you have done processing.


Even many more serious image editing programs scrap EXIF-data. Also Paint Shop Pro (at least 9) can't save EXIF data if you use progressive JPEG encoding. (using that for web pics is good because it gives rough image after downloading about 10-20% of files total siz)

I don't know why it's that way but there can't be any valid reasons for that because EXIF data is in separate packet than image data in JPEG so programs should be able to edit image without throwing it away.
E.T is offline   Reply With Quote
Old Dec 22, 2005, 3:31 AM   #7
Senior Member
 
Steve40's Avatar
 
Join Date: Dec 2005
Location: Asheville NC
Posts: 187
Default

Most photo editors have exif data viewing built in -Photo Shop does. However some formats do not peserve it for example Windows Bitmaps.
Steve40 is offline   Reply With Quote
Old Jan 4, 2006, 11:35 PM   #8
Junior Member
 
Join Date: Apr 2005
Posts: 12
Default

I have three questions regarding exif data which I hope you guys could also answer:

1. How large is exif data?

2. Is exif really stored in a separate, uhm, packet(?), from the jpeg file? I heard that whenever you open and save a jpeg file, its quality partly deteriorates. So if I use a program that alters exif data, for example, and save it, does the data of the photo sufferinadvertently?

3. Is there a way of removing exif data from the jpeg file? It seems that theres no option of not inlcuding exif data in my camera.

Any comments would be much appreciated. Thanks!
takipsilim is offline   Reply With Quote
Old Jan 5, 2006, 12:12 AM   #9
Senior Member
 
Steve40's Avatar
 
Join Date: Dec 2005
Location: Asheville NC
Posts: 187
Default

EXIF is actually the file type that your camera saves picture data in- JPEG is the compression of the file not the file itself. Each time you open a JPEG, and re-save it you loose some quality.

I convert my JPG files to TIFF to do all my processing so each step, and save, does not affect the quality. You loose all of the EXIF data when you convert file types, but it does not affect display. I have to re-convert to JPEG to print, the EXIF data does not come back never the less the print is not impared.

So since EXIF is the file type, there is no way to prevent your camera from saving in this format, unless your camera is capable of down loading images in RAW. Which in itself is another can of worms.
Steve40 is offline   Reply With Quote
Old Jan 5, 2006, 3:22 AM   #10
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

takipsilim wrote:
Quote:
I have three questions regarding exif data which I hope you guys could also answer:

1. How large is exif data?
The EXIF is part of a header in your images that contains information about an image (it's not a separate file).

EXIF is short for EXchangeable Image File Format, and can be used in both JPEG and TIFF images (although some viewers and editors may not support it in both file types). I've noticed when converting from raw using ACR and saving back to TIFF, it plugs in EXIF info that's readable by viewers like Irfanview.

But, interestingly, irfanview won't move EXIF info from JPEG to TIFF when it resaves images in a different format. So, there are some quirks with the way viewers and editors handle EXIF in TIFF files.

It should take less than 64Kb for the EXIF information in the header (although this length can be extended). My KM 5D is using 19Kb of space for the EXIF embededded in a JPEG file.

Quote:
Is exif really stored in a separate, uhm, packet(?), from the jpeg file? I heard that whenever you open and save a jpeg file, its quality partly deteriorates. So if I use a program that alters exif data, for example, and save it, does the data of the photo sufferinadvertently?
No, it's a header that can be embedded in JPEG or TIFF files. It's not a separate file.

As far as resaving a JPEG file, see JPEG Images: Counting Your Losses by Mike Chaney.

Note that it's possible to modify EXIF information without degrading an image using a utility designed just for modifying the EXIF (you could update the EXIF data without loading and resaving the entire image).

Quote:
3. Is there a way of removing exif data from the jpeg file? It seems that theres no option of not inlcuding exif data in my camera.
Sure, Photoshop's "Save for Web" option removes the EXIF (probably to save space, since it could add too much to smaller images when web masters want pages with images to load as fast as possible).

Irfanview (free from http://www.irfanview.com ) is a good tool for this purpose also. When you use the "save as" option, you'll see checkboxes to retain or discard both the IPTC and EXIF information.

Also, a number of editors will always discard the EXIF (even if you'd rather keep it).


JimC 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 5:11 PM.