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File Formats

Welcome to acronyms 101 — JPEG, TIFF and RAW

Finally we've come to something that is standard across all the digital cameras. Imagine that. Something that everyone agreed on!

When digital cameras store photographs on removable media cards, they can compress the photo to save room on the card. This lets you take more photos. The compression will affect the quality of the photo, but unless you really want to make large prints of your photographs, you may not notice.

When you say RAW, do you mean it's not cooked?

The three main file formats for digital photographs are RAW, TIFF and JPEG. Both RAW and TIFF formats do not apply any compression to the photo to save space on your memory card. When your camera saves a digital photo as a RAW or TIFF file (if it can), the photo includes all of the information captured by your camera's image sensor.

JPEG is a far more common file format, and it does use compression. It is a much more popular format with the consumer market because it allows a 128 MB media card to store a ton of photographs.

This is the difference in file size between a photo saved with the RAW/TIFF (uncompressed) format and a photo saved in the JPEG (compressed) format:

RAW / TIFF File SizeJPEG File Size
3.4 MB1.3 MB

And this is the number of photos that you might expect to be able to take using a 128 MB removable media card:

RAW / TIFFJPEG
38 photos98 photos

It is a HUGE difference. But there's even more to it.

JPEG Compression

We already know that a digital photograph stored in the JPEG format means that the file sizes are smaller which means a removable media card can store more photos. The extra information is that on many digital cameras you can determine HOW MUCH compression you want to use.

JPEG files can either be mildly compressed or substantially compressed. Cameras will typically let you set two or three levels of compression. If you are willing to set your camera to the highest compression level, you get even more mileage out of your removable media card:

JPEG Low CompressionJPEG High Compression
1.3 MB0.7 MB

And this is the number of photos that you might expect to be able to take using a 128 MB removable media card:

JPEG Low CompressionJPEG High Compression
98 photos183 photos

Again, this is a huge difference.

So what's the catch?

You're now feeling that probably everyone who owns a digital camera always has their camera set to store digital photos in the JPEG format with high compression. When you can get 183 photos onto a 128 MB card, that makes sense right?

There's always a catch. In this case, photographs that have been compressed a lot lose some of their detail and start to show grain. This effect is similar to when you choose a high ISO setting on your camera.

RAW (No Compression)
This is a photo with no compression applied to it.
RAW (No Compression)

JPEG Low Compression
Same photo, same angle, same aperture, shutter speed and ISO setting.The only difference is that this photo was saved in the JPEG format, with low compression.
JPG Low Compression

JPEG High Compression
Same photo, same settings, just more compression.
JPEG High Compression

JPEG High Compression Detail
In order to make the grain of a compressed JPEG clearer, I have included this detail of the compressed photo.
JPEG High Compression Detail

Can you see the difference? You may not be able to at the image size that I have included here. If you had the original photographs on your computer at home the differences might be more evident.

This does illustrate a good point about compression: you can only tell that an image has been compressed if you know what you are looking for. If you're not into professional imaging, and want to get the most mileage out of your removable media card, then set your camera to JPEG with high compression.

The Basic Rule of Thumb

Not all cameras will let you save photos in the RAW and TIFF formats. The default setting for cameras that do let you is JPEG. JPEG is also a file format that is easy to share with others via e-mail. Sending a RAW file to someone is NOT a good idea (due to the substantial file size).

If you are a professional photographer and quality is very important, then buy a camera that can save in RAW and TIFF, and set the camera to these formats.

If you are not a professional, but enjoy high-quality photos, then you should be perfectly happy setting your camera to JPEG with low compression (the default for almost all digital cameras).

If you really are not that picky about the quality of the photos that you take, and want to maximize the use of your removable media card, set your camera to JPEG with high compression and take as many photos as you like.

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