Q and A: Raw capture mode is confusing. Can you help?

Question

I need some advice about using RAW capture mode. I have just started shooting in RAW mode but after some research on the Internet, I still have some questions about RAW. Why won’t Photoshop CS3 or Elements 7 open and convert the RAW files from my EOS T1i? Also, when using the Canon DPP software, should I save the photos to an 8-bit Tif or a 16-bit Tif. L.V.

Answer

The software that’s bundled with any DSLR certainly supports the unique RAW format produced by that camera. However, versions of Photoshop that are older than CS4 – such as CS3 – do not support the newer cameras’ formats.

That’s because Adobe ceased supporting the older versions. Both Elements 6 and 7 do support the RAW files produced by most of the recent cameras, including the T1i. Anyone who cannot open a RAW file with Elements 6 or 7 will need to download and install the Adobe Camera Raw plug-in version 5.5. See Adobe for the download and for installation instructions. (Photoshop CS4 owners should note that they may also need version 5.5 or later.)

All versions of Photoshop Elements - since version 6 - can support all of the latest DSLRs' RAW formats. Of course, with newer cameras, that may require installing the latest version of the Adobe Camera Raw plug-in.  ©2009 Peter K. Burian
All versions of Photoshop Elements since version 6 can support all of the latest DSLRs RAW formats Of course with newer cameras that may require installing the latest version of the Adobe Camera Raw plug in ©2009 Peter K Burian

The default with any RAW converter is 8-bit per channel color depth when converting to the TIFF format from a RAW file. Most converter programs also allow you to select 16-bit TIFF. A 16-bit image contains substantially more colour and tonal values: over 4000 intensity levels vs. 256 levels for each pixel. That allows for making more significant changes to an image without posterization: a loss of smooth gradations in tone and color.

On the other hand, stick to 8-bit TIFF unless your image editing software provides a great deal of compatibility with a 16-bit file, such as Lightroom, Aperture 2.2, Photoshop CS3 and CS4.

Whether you use the camera maker's software, Photoshop Elements or just about any other versatile converter, you can save a TIFF file in either 8-bit or 16-bit color depth. The latter has benefits but only for those who own image editing software with extensive support for 16-bit files. (Canon Digital Photo Pro screen)  ©2009 Peter K. Burian
Whether you use the camera makers software Photoshop Elements or just about any other versatile converter you can save a TIFF file in either 8 bit or 16 bit color depth The latter has benefits but only for those who own image editing software with extensive support for 16 bit files Canon Digital Photo Pro screen ©2009 Peter K Burian

After your 16-bit file looks perfect – and will need no further adjustments – convert it to 8-bit. (With CS3, you can do so with this command: Image > Mode > select 8-bits/Channel.)

I recommend this step because 16-bit files are huge: twice the size of 8-bit files. Unless you have vast amounts of storage space in your computer (or an external hard drive), you’ll prefer to store the much smaller 8-bit TIFF photos.

You should also print from an 8-bit TIFF. While some software (such as Aperture 2.2) allows for printing from a 16-bit file, Adobe products do not. Even if they did, there is really no great value in printing from the 16-bit TIFF; this is another reason why you may want to save only 8-bit files.

This Post Has 6 Comments

  1. At least some Adobe products do print from 16 bit TIFF files, so there’s no need to convert to 8 bit file before printing. Photoshop CS3 on a PC definitely does!

  2. I ran into the camera raw conversion for Photoshop CS2 when I bought a Nikon D90. My solution, the Adobe recommended one, was to download the Adobe DNG converter. As near as I can tell, it preserves all the advantages of RAW files with a file size less than TIFF. The only problem is you end up with two copies of the file.

  3. Mike: yes, it may be possible depending on the software and computer platform, but there’s no real value to doing so. AND you must have a printer that can print from 16-bit files …. only a few printers can do so. Peter

    Here’s some info from Tim Grey, Nov. 2 AND Nov. 11, newsletter ….The Ask Tim Grey eNewsletter is free. Details on becoming a member can be found here: http://www.timgrey.com/asktimgrey/

    PRINTING: For all practical purposes, the real world difference between 8-bit per channel and 16-bit per channel printing is non-existent. You simply can’t see a difference between the two prints. **The option to print 16-bit data is only available with a handful of printers***, using either Photoshop CS4 or Lightroom 2, and only on the Macintosh platform (for now). The benefit is incredibly minimal, and in most cases you would not be able to see any
    difference.

    The benefit would really only be in very smooth gradations, which can be maintained better with 16-bit printing (you’ll likely see slightly more banding in those gradations with 8-bit printing).
    If you’re working with a 16-bit per channel workflow (which I do highly recommend) and you happen to have a printer and the necessary software configuration to enable 16-bit per channel printing, I would certainly enable it just to provide every possible advantage in terms of print quality.

    But I certainly wouldn’t buy a new printer, switch platforms, or buy new software for the sole purpose of enabling 16-bit printing, because there simply isn’t a significant benefit. Most people would never know the difference with most images.

    ………. 16-bit per channel mode ……………… Upon export you would need to decide whether it was necessary to have the images in 16-bit per channel mode. If you are exporting the images for purposes of creating some form of output (printed or online display, for
    example), there’s no need to export the images in 16-bit per channel mode.

    If you’ll be making further adjustments to the images using Photoshop or another
    tool, then I recommend exporting as 16-bit per channel.

    The bottom line is that 16-bit per channel can offer a benefit in terms of quality for your images, and I highly encourage its use. Just keep in mind that just because 16-bit per channel is certainly helpful when optimizing your images doesn’t mean it will be helpful at later stages of your workflow.

    Become a Member The Ask Tim Grey eNewsletter is free Details on becoming a member can be found here: http://www.timgrey.com/asktimgrey/

  4. Steve: I have not used DNG converter.

    Does that allow for converting any RAW file to DNG? Even if CS2 does not support that camera’s RAW format?

    Or do I misunderstand what DNG converter does? Peter http://www.peterkburian.com

  5. Thanks for your kind note, Ingeborg. I don’t write about Photoshop usually but this topic is quite important.

    Peter

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