Comments on: Photographic File Formats

By: Jared

Jared — Tue, 22 Apr 2008 02:59:21 +0000

John,

Nice article, informative and accurate. One other advantage to RAW files is that edits to them are non-destructive. When working with JPG files, each edit modifies the image data, and being digital, each edit therefore degrades the image a little due to truncation error. With RAW, all edits are done in memory, and the image data is never modified. When all the edits are complete to the photographer’s liking, the image is rendered to a JPG or TIFF file, all at once, minimizing truncation error and preserving all the original image data (i.e., the RAW data never changes). The image can be reset to its original condition at any time. In addition, multiple edit “recipes” can be saved in the form of XML sidecar files (or sometimes stored inside the RAW file), which takes up less space than making entire copies of the image.

Jared

By: Chuck

Chuck — Sun, 20 Apr 2008 15:10:42 +0000

Excellent article. Thank you for taking the time to write it and very clearly. I know understand much of what my cemera is doing.

By: Jon Vermilye

Jon Vermilye — Sun, 20 Apr 2008 14:51:40 +0000

David –

Thanks for your comment. I do have HDR on my list. I hope to cover both manual methods of creating them as well as some of the “automatic” software. HDR is a real boon to the theatrical photography I shoot…

john b –

You are right – I should include GIF, although iI don’t consider it a photographic format. The problem with GIF is it uses a maximum of 256 colors. Although this is enough for graphics and some photographs, it will cause banding in gradual color variations such as skies, etc. It does have the advantage that GIF files are usually the smallest format available. As to the other formats available, I tried to cover those available from your camera. If I tried to cover all of them I’d end up rambling on even longer than usual!

Thanks for your reply.

JRV

By: john b

john b — Sun, 20 Apr 2008 12:51:24 +0000

Excellent article, thanks for clarifying a confusing issue with most amateurs, but it would really help if you would follow up or include the other formats we see. Gif is one and I think there are some more.

The real value in understanding size and quality issues of all is also important for those who want to upload images to sites, blogs, craigs list, ebay whatever that often have limited size issues. Also I have found lately some individuals web services limit file sizes and all too often I get rejected emails.

Thanks for clarifying a complex issue.

john b

By: David

David — Sat, 19 Apr 2008 19:29:15 +0000

This is one of the better articles I’ve read for amateur photographers. I might also point out that because of its data, RAW can also be used to generate a High Dynamic Range image more easily than any other format short of taking multiple shots of a given scene with different aperture or shutter-speed settings between them.

I hope you discuss this very interesting subject in one of your upcoming blogs.