Compression for Raw


Today’s Question: When shooting Raw with my Fujifilm cameras, should I shoot Lossless Compressed or Uncompressed? The Fujifilm manual states that if I shoot on Lossless Compressed, “Raw images are compressed using a reversible algorithm that reduces file size with no loss of image data.” Which would you use?

Tim’s Quick Answer: I recommend using Lossless Compressed when such an option is available for raw captures on your camera, provided the software you’re using to manage your photos supports that compressed raw capture format.

More Detail: I think just about all photographers are familiar with the raw capture option available with most digital cameras, and hopefully most photographers are taking advantage of this option. A variation on a normal raw capture that is available with a variety of camera models is a compressed raw format. That generally involves a compressed format that is “lossless”.

When compression is lossless, it means that no information is lost as part of the compression. In other words, the information is described in a more efficient way, without actually altering the underlying information. For example, instead of describing a row of ten pixels, all of which are blue, by repeating “blue pixel, blue pixel, blue pixel” until you’ve listed off ten blue pixels, you could simply say “ten blue pixels”.

Obviously, the actual process is a bit more complicated in the context of a full digital photo recorded in a raw capture format. But the point is that with lossless compression there is no risk of losing any of the original data, based on how the algorithms are written.

And, of course, by making use of lossless compression you will be able to fit more captures on your media cards and download those smaller files to your computer more quickly.

The only caveat of lossless compression for raw capture is that some software may not have been updated to support the lossless compressed format in addition to the uncompressed raw format. However, in my experience this is not an issue. For example, Adobe Lightroom Classic and Adobe Photoshop support compressed versions of various raw capture formats.

So, my recommendation is to make use of the lossless compression option for raw captures if your camera supports that option, and if the software you’re using to manage your photos also supports that format.