*.THM files in RAW mode

I've got an EOS 10D, which I dearly love. When shooting in RAW mode, I get a second copy of each image that has the extension .THM. These are tiny little images with extremely low resolution and I have no idea what purpose they serve, if any. I find them annoying as I just end up deleting them.

Can anyone tell me anything about what purpose they serve, and is there a way to stop the camera from saving them?

Thanks.

They are thumbnails of the raw file. Makes it easier to display them in programs such as EVU instead of converting the raw file each time they are displayed. They also contain EXIF information that is not stored in the RAW files themselves so unless you really don't care about the EXIF info, I wouldn't go deleting them all if I were in your shoes. I personally keep every one of these .THM files. AAMOF, on my XP system, I have my registry set up to treat .THM files as JPEG files so that I can see these file in thumbnail mode via Windows Explorer. That makes it easy for me to see exactly what the RAW files are in Explorer without me needing to open them in EVU or any other image editing program.

EXIF info is stored in RAW and CR2 files. My 300D created the THM files, I deleted them, and I still had full EXIF.

There's a free little program around that lets Windows preview RAW/CR2 files, plus IrfanView can view them too, so there's no need for THM files. It's on a thread somewhere around here, if you can't find it PM me and i'll look at home later.

I used this guide to have windows show thumbnails for my raw files. it only works in windows XP though.

http://www.suodenjoki.​dk …rticles/raw_thu​mbnail.htm

Are you absolutely sure of that? Full?

---Bob Gross---

The RAW contains basic Exif.

But the THM has some extra stuff in it.

Yes, that is the way mine always was.

Apparently Tim's is different.

---Bob Gross---

Mine's more like Tim's. It could be different with different camera model's. I have 300d like Tim.

Bob
totally agree with you on this one.
realised some time ago different people seem to have various amounts of info shown in there exif
file per image.
without these small (info files if you like) some info is not with the raw file.
I believe about 29 lines of info to be the full list
but I guess this may well vary with cameras etc. etc. Just checked this on a raw shot with 1D mk 2

A useful little bit of software so raws can be displayed as thumbnails with windows is DP magic comunity edition.
hope this helps.
personally i would not delete these info files

http://www.dpmagic.com​/

Martin (Huckaback Photo)

Just had a check, the EXIF in a RAW from my 300D has shutter speed, aperture, EC, metering mode, flash fired (yes/no), focal length, ISO, exposure mode (eg aperture priority), and a couple of useless fields. It's possible the thm file has more information in it, but none that i've ever wanted to know.

It's ok, Tim, we all make mistakes.

I might be wrong, but I think some of the other dSLRs have none of the exif in the RAW. Not sure about the 10D, though.

There is a point here, gang. The point is that EXIF may be a standard, but the implementation of the standard is inconsistent among different brands and different models.

Although a .THM file is unnecessary to some users, it does carry EXIF information that is of value through some programs. Just because the information is there, you can choose to ignore it.

In my view, the .THM files were so tiny, as compared to the main file, that it made little difference in file capacity on any storage media. So, I figured I would keep them.

---Bob Gross---

pcasciola wrote:
It's ok, Tim, we all make mistakes.

I made a mistake? Never?!

What exif information is available in a thm file that's not in the RAW?

The first attachment is a screen print of the EXIF info in the CRW file.
The second attachment is a screen print of the EXIF info in the THM file.

BTW, if the two files are together, the program you are using to view the EXIF info will merge the info from both files. So see the their respective EXIFs individually, you have to put them in separate folders.

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what program is that? I'd like see what it looks like with a file from a rebel.