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Image File Formats

There are five main image file formats used in digital photography.  In this article, I am going to describe each of these file types, and when they should be used.

JPEG

JPEG is the most common file format used in digital photography, and on the Internet.  This is basically due to file size, since images on web pages and sent via email need to be small.  This smaller file size is really the only upside to the JPEG file format. The downside to JPEGs is that in order to compress the image data to a smaller size, there is always going to be some loss of quality in the image.

Sometimes this loss is very subtle and doesn’t even matter for some purposes.  Other times, it can make a big difference in the final image. Also, anytime you make a change to a JPEG file, and then save it, even more data is lost.  This can really add up if you are changing and saving the same image multiple times. Whenever possible, it is always going to be better to shoot in RAW, convert to TIFF while editing, and then only save to JPEG once when you are completely done editing your image.

If your camera doesn’t take RAWs, then convert the JPEGs straight out of the camera into TIFFs prior to post-processing them.

TIFF

Unlike JPEGs, TIFFs are “lossless”, and therefore contain all the original image data.  Also, making changes and saving won’t result in any loss of data.  For this reason it is always recommended that you convert your RAWs and/or JPEGs into TIFFs for editing. The downside to the TIFF file format is the very large size.

PNG

The PNG image file format is another “lossless” format.  PNG images are also somewhat smaller than TIFFs, which can be an advantage.  However, some web applications still can’t properly read a PNG, and there can be problems with the GAMMA values not being read correctly.  This is less so these days than it was a few years ago however. Personally, I use PNGs only when I need the background of my image to be transparent.  For example, the logo for this website is a PNG file.  If I had used a JPEG there would be a white rectangular image file with the logo in it.  Tacky!

GIF

GIFs, like PNGs are great for images with transparency.  It is also the only image format that supports animation.  So, all of those animated web banners you have seen are all GIFs. GIFs are really only suited for web viewing, and appear posterized when used in printing.

RAW

The RAW file format is the digital version of the film negative.  There is of course a longer technical explanation of the RAW file, but in simple terms it is the “raw” pixel data exactly as the digital sensor read it. Most digital cameras automatically convert RAWs to JPEGs.  However, DSLRs give you the option to shoot in either RAW, JPEG or both.  Since the camera needs to make its own interpretive decisions when converting from RAW to JPEG, converting the RAW yourself on your computer, allows for more final control of the image.

Also, each camera has its own RAW file format, so it is not a standardized file type such the JPEG and TIFF.  For this reason, you have to make sure that the RAW converter you use is compatible with your camera type.  As new cameras are released on the market, RAW conversion software needs to be updated as well.

image file formats

JPEG after being saved 275 times

2 Responses to Image File Formats

  1. Sara says:

    My husband just bought me my first DSLR and I am by NO means even an amateur photographer, but I am determined to learn 🙂 So I HOPE this isn’t to stupid of a question. I have read only a little about shooting RAW images and I read that one of the downsides of shooting RAW was the editing time required after shooting. It was said that the majority of editing had to be done afterward – how does this differ from shooting in other file formats?

    • There are no stupid questions! We all have to learn these things at some point. Only a few years ago I didn’t even know what a RAW file was. That being said, I think that the majority of the time setting your camera to shoot in JPEG is just fine. All digital cameras actually shoot in RAW and then convert to JPEG in camera. When you are shooting in RAW the camera just doesn’t do the conversion for you. This can give you a ton of control over the image if you have RAW conversion software, but if you don’t know what you are doing then this could be very tedious and ultimately not worth it.

      Personally, I tried shooting in RAW for awhile and found it to not be advantageous. That’s just me though. What I prefer is to immediately convert my JPEGs to TIFFS. This was there will be no loss of quality after I edit and save. Each time a JPEG is saved it loses some quality due to image compression.

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