File Names?

[BruceMcL]

I am brand new to digital photography (my EOS 300D is only two days old. So I'm going to have a lot of beginners questions and here are some.

I transferred my firsst few shots from the flash card to my computer. When I looked in the folder on the computer hard disk I noticed that each shot had two files. One was a CRW file of about 7 mb. I believe that is the raw file. But there was also THM (?) files of around 10 mb or so. What are those files? Are they useful for anything?

I read that shooting in raw mode was useful for ensuring highest quality at printing time. But I don't think the Photoshop elements program can handle them. I guess the CRW files must first be converted to JPEG. If that is so, does that limit the eventual print quality? And if raw files must be converted why not shoot in JPEG from the beginning? I know I am missing something here, I just don't know what. I do want the ability to make 11X14 or larger prints with very good quality.

I come from a medium and large format film background so perhaps I am expecting too much. Most of the pictures I have seen in the net galleries look very good but I also realise they are low resolution. I'm not sure what to expect when some of my shots are finally printed by a (probably Epson) printer.

Any help would be most appreciated.

[robertwgross]

You are partly correct on some things.

When you transfer files from CF to the computer, you will get one big CRW file (RAW format) of about 7MB, and then you will get one THM file, but it won't be 10MB. More like 5K-10K bytes.

So that gets the CRW file onto the computer. Then you convert from CRW to (probably) TIF, and the Canon utility will do that. Once in TIF, you can edit it using any of a number of image editors (Adobe Photoshop, Corel, etc.).

Alternatively, if you know the images are perfect straight out of the RAW file, then you could convert to JPEG or anything else.

Now, if you came from the film world (like most of us), think of the RAW file as the negative. You know you can get a negative printed lighter or darker or with other alterations. I archive the RAW files away, just as I might a film negative. I can always fall back to the RAW file if I have to.

Once into JPEG, you've crowded yourself into a corner, and you have little room to make big adjustments to the dynamic range.

Similar to you, I also print up to 11x14 on an Epson printer. I generally print from a 24-bit TIF file.

---Bob Gross---

[PacAce]

BruceMcL wrote:
I transferred my firsst few shots from the flash card to my computer. When I looked in the folder on the computer hard disk I noticed that each shot had two files. One was a CRW file of about 7 mb. I believe that is the raw file. But there was also THM (?) files of around 10 mb or so. What are those files? Are they useful for anything?


The THM file is nothing more than a small JPG file that is used as a thumbnail. As a matter of fact, if you rename the .THM extension to .JPG, you'll be able to view the file with any software that handles JPG files, including Windows Explorer.

Although some people don't bother keeping the THM file, I like to keep it around with the CRW file so that, with Windows Explorer, I can tell what image the CRW file contains. Windows Explorer allows you to view image files as a thumbnail. Obviously, it can't display the CRW files as a thumbnail. However, because the THM file is a JPG file, it can display the THM files as a thumbnail. But there's a catch (isn't there always? :) )

You have to either rename all the THM extensions to JPG so that Windows explorer will recognize the extension, or you have to tell Windows Explorer that THM files are JPG files by creating an entry in the Windows registry. The later options is the smartest and the easiest to do. Here's how:

If you have Windows XP, create a file called "THM.REG", key in (or cut-n-paste) the following and save the file:


[HKEY_CLASSES_ROOT\.thm]
"PerceivedType"="image"
@="jpegfile"
"Content Type"="image/jpeg"
"PISaveOption"=dword:00000001

[HKEY_CLASSES_ROOT\.thm\OpenWithProgids]
"jpegfile"=hex(0):

[HKEY_CLASSES_ROOT\.thm\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"


Using Windows Explorer, select the file you just saved and double click on it. You should get an acknowledgement that the registry was updated. That's all there is to it. Now, you can go into Windows Explorer and double click to open it just like a JPG file. Or, change the View in Windows Explorer to Thumbnail and all the THM files will be displayed as a thumbnail.

Use the following if you have Windows 2000 instead:


[HKEY_CLASSES_ROOT\.thm]
@="jpegfile"
"Content Type"="image/jpeg"

[HKEY_CLASSES_ROOT\.thm\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"

[HKEY_CLASSES_ROOT\.thm\ShellEx]

[HKEY_CLASSES_ROOT\.thm\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}]
@="{7376D660-C583-11d0-A3A5-00C04FD706EC}"

[BruceMcL]

Thank you so much. You have offered some very helpful explanations. I was using the Canon software to convert the raw files to JPEG. I will now try tif files as fodder for Photoshop.

I have a lot to learn. I will make progress slowly

Bruce

[Hatem Eldoronki]

PacAce wrote:

If you have Windows XP, create a file called "THM.REG", key in (or cut-n-paste) the following and save the file:


[HKEY_CLASSES_ROOT\.thm]
"PerceivedType"="image"
@="jpegfile"
"Content Type"="image/jpeg"
"PISaveOption"=dword:00000001

[HKEY_CLASSES_ROOT\.thm\OpenWithProgids]
"jpegfile"=hex(0):

[HKEY_CLASSES_ROOT\.thm\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"


Using Windows Explorer, select the file you just saved and double click on it. You should get an acknowledgement that the registry was updated. That's all there is to it. Now, you can go into Windows Explorer and double click to open it just like a JPG file. Or, change the View in Windows Explorer to Thumbnail and all the THM files will be displayed as a thumbnail.

Use the following if you have Windows 2000 instead:


[HKEY_CLASSES_ROOT\.thm]
@="jpegfile"
"Content Type"="image/jpeg"

[HKEY_CLASSES_ROOT\.thm\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"

[HKEY_CLASSES_ROOT\.thm\ShellEx]

[HKEY_CLASSES_ROOT\.thm\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}]
@="{7376D660-C583-11d0-A3A5-00C04FD706EC}"



I tried your script, but I got a window saying something about not being able to do this except from the registry editor...I got XP.

[PacAce]

mcouper wrote:
I tried your script, but I got a window saying something about not being able to do this except from the registry editor...I got XP.


Hmm, that's odd. You do have administrator privileges on your XP machine, right? If not, that may explain the message.

If you can't double click on the .reg file to update the registry, see if you can update it directly from the registry editor:

1. In Start | Run, type "regedit"
2. When the Registry Editor comes up, select "My Computer" at the top of the tree.
3. Then click on File and select Import... from the menu.
4. In the Import Registry File panel, select the .REG file you created.

If that still doesn't work for you, then I'm pretty sure you don't have admin privileges on the machine you're on.

[katbowen]

I hope that you can help me, I found this thread whilst searching in panic on the internet about THM and CR2 files. I have a canon 5D and yesterday returned from holiday and accidentally deleted one of the folders from the lexar flash card whilst it was in the usb card reader. I managed to recover the missing images but they have been restored as CR2 and THM files. Having read this post i am not concerned about the CR2 files, I have downloaded a microsoft viewer for the RAW files so i can see thumbnails of these now. I updated my registry as per the below script to tell the pc to view the thm as jpeg and they are now showing as jpeg but are still not showing me previews as thumbnails in explorer! Can you offer any more help? Ideally i would like all my pictures to show thumbnails and to be visible in my epson printing software- at present they do not show.

Thank you in advance Kat- feel free to write to kat@katbowen.com because i am new to any kind of chat room and need help with this urgently!

Kat

[PacAce]

Since the 5D does not use .THM files (as far as I know), I'm assuming that they are real JPEG files and not thumbnail files. If that's the case, all you need to do is rename the extensions from .THM to .JPG and you should be back in business.

BTW, welcome to the forum! :)

[Eagle]

Obviously, it can't display the CRW files as a thumbnail.

RAW Image Thumbnailer and Viewer

Are you a serious photographer? Now you can organize and work with digital RAW files in Windows Explorer (much as you can with JPEG images). This tool provides thumbnails, previews, printing, and metadata display for RAW images

http://www.microsoft.com/windowsxp/using/digitalphotography/prophoto/raw.mspx

[PacAce]

RAW Image Thumbnailer and Viewer

Are you a serious photographer? Now you can organize and work with digital RAW files in Windows Explorer (much as you can with JPEG images). This tool provides thumbnails, previews, printing, and metadata display for RAW images

http://www.microsoft.com/windowsxp/using/digitalphotography/prophoto/raw.mspx
If you look at the date of that post you quoted you'll see that it was made way back in 2003. :rolleyes:

And, no, I'm not a serious photographer. I do if just for funzies! :mrgreen: