You may have noticed that your camera offers a few different photo quality settings. These are available on almost any model in the market today, whether it is a point-and-shoot or a digital SLR. Oftentimes, they are labeled as “low,” “normal,” or “fine.” Some camera companies use their own proprietary quality standards such as SQ, HQ, and SHQ (standard, high and super high quality respectively).
So what's the difference? The quality setting you use determines the amount of compression your camera applies to the image. SHQ or Fine quality means low compression whereas SQ or Low quality means high compression.
Why is compression needed?
JPG image format
Most cameras save their images in what's called the JPEG (or JPG) format. This format was invented to help make image sizes more manageable. It does this using compression. It removes parts from the image in a clever way so that when the image is displayed again, you won't notice those elements missing.
So a 6 megapixel photo that would need 18 megabytes to store only needs around 4 megabytes when saved in a JPG format. So you can get over 4 times as many photos on your memory card. (There are other storage formats. Check out my tip on image file formats for a more comprehensive discussion.)
Quality = Compression
Your camera can increase or decrease the level of compression it uses on a photo. And this is what the image quality setting changes - the amount of compression used. A high quality setting uses the least compression. A low quality setting uses the most compression, but it also makes your image look much worse.
High Quality = Low Compression = Great Image = High Space Requirement
The High Quality setting will give you a great looking image, but also takes more space on your memory card.
Low Quality = High Compression = Poor Image = Low Space Requirement
The Low Quality setting will save you lots of storage card space so you can get more shots, but at the sacrifice of picture quality. Your images won't look as good - particularly if you print them out.
Notice the image on the right. While I have exaggerated the effect to illustrate the point, you can see the effect on your image when you use a low quality setting.
Some cameras allow you to change the resolution of your image as well as the image quality. Resolution is tied to megapixels. So your 6 megapixel camera will use all 6mp when on the highest resolution setting, but will use 4mp on the medium quality resolution, and only 2mp on the lowest setting. While this results in a huge file savings (halve the megapixels, and you half the card space used), it also means you get half the image quality, and in most cases lose the ability to have your photo look great when printed on a large canvas.
Shoot at the Highest Quality All the Time
I recommend always keeping your camera on the highest quality setting it supports. If your camera supports different resolutions, always choose the highest. Why? You never know when you’re going to take the picture of a lifetime. You might not be considering making large prints of your work right now, but what if you took a picture so amazing that you had no choice but to proudly display it in the largest size possible? What if your photo were so great that it could win an award? A low quality version of the photo would not get past the editor's desk if you tried to submit it to a magazine or photographic association.
If you always run out of card space because of the high quality setting you use, it's much better to upgrade your card than downgrade the quality setting.
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