Why does a Photographer erase the EXIF info before posting.....

I have noticed that HDR images loose the EXIF data.

I understand your friend's perspective. I have used the EXIF data of other photographer's to help give me some ideas when I didn't understand how to accomplish certain things. I didn't usually use the EXIF data as the end point, but often the starting point to help me do better searches for articles about the desired effect.

Thalagyrt wrote in post #11052064
No, it's really not that big. EXIF is just a set of headers and takes up around 1-4KB, generally around 1 or 2 KB from what I've seen when dissecting images to pull out the ITPC headers, which encompass far more than EXIF and are in every JPEG/TIFF anyway. It's part of the TIFF spec and EXIF/ITPC data in a JPEG is nothing more than an embedded TIFF with no image data.

Technically you may be right, but to most people EXIF means any embedded metadata regardless of whether it is actually IPTC, EXIF, or any other form of data. For most photographers there is no need to understand such differences, and a lot of tools use EXIF as the catchall term for viewing and manipulating metadata.

But with embedded thumbnails and preview images it is very possible to see drastic differences in file size as as ccp900 suggests by saving a file with and without metadata. The first time I used PS CS5 I was shocked at the size of an image using Save For Web before discovering there was a 'keep metadata' option as it seems to be all or nothing.

Michael.

mij wrote in post #11064189
Technically you may be right, but to most people EXIF means any embedded metadata regardless of whether it is actually IPTC, EXIF, or any other form of data. For most photographers there is no need to understand such differences, and a lot of tools use EXIF as the catchall term for viewing and manipulating metadata.

But with embedded thumbnails and preview images it is very possible to see drastic differences in file size as as ccp900 suggests by saving a file with and without metadata. The first time I used PS CS5 I was shocked at the size of an image using Save For Web before discovering there was a 'keep metadata' option as it seems to be all or nothing.

Michael.

Ah, good point. I forgot about the embedded previews. I've never dug into those sections of the files as I have no reason to look at them.

Save to web strips exif info from the images as well. I always save as jpeg then post.

Along the lines of "more things in Metadata than you realize", not only the camera but processing programs dump stuff into your metadata, Lightroom and Photoshop/ACR, DPP, all that. If you want to be entertained, open a file in Photoshop/Bridge, open the file Info and then expand all the details listings. Fun and games! And all that is encoded into the saved jpeg! At least I believe it all is...

S.E.V. wrote in post #11066448
Save to web strips exif info from the images as well.

Only if you tell it to. There are options that allow you to save all metadata.

tonylong wrote in post #11066527
If you want to be entertained, open a file in Photoshop/Bridge, open the file Info and then expand all the details listings. Fun and games! And all that is encoded into the saved jpeg! At least I believe it all is...

No, it isn't.

Peano wrote in post #11066583
No, it isn't.

Ah, OK, that gets left out with the conversion, so it only shows up when you are working with Raw data?

What p*sses me off is that photo sharing sites (Zenfolio in my case) strip all the IPTC info including contact info and copyright status when you use their re-sized hotlinks.

I end up having to maintain an entire "mirrored" world of 1024X images so that I can share them here and keep the info through sharing original images.

tonylong wrote in post #11066731
Ah, OK, that gets left out with the conversion, so it only shows up when you are working with Raw data?

Sorry, I think I got that wrong. After a few tests, it seems that all the data is stored with the jpeg. You can access it with Photoshop (file info), but in a viewer like IrfanView, you see only part of the stored info.

In any case, it adds very little to the file size, so it isn't worth stripping on that account. I would strip it only if I had some reason to keep people from knowing my camera settings.

Peano wrote in post #11068583
Sorry, I think I got that wrong. After a few tests, it seems that all the data is stored with the jpeg. You can access it with Photoshop (file info), but in a viewer like IrfanView, you see only part of the stored info.

In any case, it adds very little to the file size, so it isn't worth stripping on that account. I would strip it only if I had some reason to keep people from knowing my camera settings.

OK, now then I was referring not just to the common camera settings but to both the "maker" settings (where the Canon proprietary info used by DPP gets stored) and also to the fact that processing info gets stored by software such as Photoshop/Lightroom/Ca​mera Raw.

It's more of a curiosity and interesting info thing -- I just went to a jpeg in Bridge and did a File Info thing. In the Advanced listing, there were two "segments": Adobe Photoshop Properties, which was not very populated because I had not opened/processed the image in Photoshop proper, but more interesting was the "camera-raw-settings. Open that segment and I got the entire history, every tweak I had done to the Raw file (in Lightroom, I believe) and it was stored in the jpeg. I think it's interesting, the amount that can be saved, viewed and retrieved...some people may prefer to not have all that info in there...

tonylong wrote in post #11068649
OK, now then I was referring not just to the common camera settings but to both the "maker" settings (where the Canon proprietary info used by DPP gets stored) and also to the fact that processing info gets stored by software such as Photoshop/Lightroom/Ca​mera Raw.

It's more of a curiosity and interesting info thing -- I just went to a jpeg in Bridge and did a File Info thing. In the Advanced listing, there were two "segments": Adobe Photoshop Properties, which was not very populated because I had not opened/processed the image in Photoshop proper, but more interesting was the "camera-raw-settings. Open that segment and I got the entire history, every tweak I had done to the Raw file (in Lightroom, I believe) and it was stored in the jpeg. I think it's interesting, the amount that can be saved, viewed and retrieved...some people may prefer to not have all that info in there...

That's all stored in a sidecar file, not the image itself. All of the ITPC data, including but not limited to EXIF, is stored (or should I say can be stored?) in the JPEG as an embedded TIFF.

Thalagyrt wrote in post #11069600
That's all stored in a sidecar file, not the image itself. All of the ITPC data, including but not limited to EXIF, is stored (or should I say can be stored?) in the JPEG as an embedded TIFF.

Hmm, I'll have to check it out! I've been hopping between computers recently.

So...time for another round -- none of the jpeg files I've checked have sidecar files associated with them or even in a directory with them, and yet each (which was processed from Raw file in Lightroom then exported into separate directories with the Minimize Metadata option unchecked has a full section on camera-raw including all my LR edits in the Metadata. But no xmp files are created by my LR catalog.

Now, am I the only one seeing this? Anyone interested in testing this out? Or James, if you really think it's a sidecar file, where the heck is the sidecar file?

OK, guys, ready for another tidbit?

I converted a jpeg to a straight text document and opened it and did a search for "camera-raw" and there it was! in there with all the embedded exif/metadata stuff, a whole section with very detailed Raw conversion settings!

Now, this would be Adobe proprietary stuff and not visible to outside apps (for example, DPP does not show this stuff in Info nor of course would Opanda. But, when I upload an image to, say, PBase, my original image has all that stuff, so if you were to actually save the original image, it would all be there to examine in Photoshop!