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Image Quality Settings

In this article, you will see how you can control the parameters that affect the quality of the image that is being captured. These are critical settings that will significantly influence the final output. There are essentially three parameters that influence the overall quality of the captured image. These are:

  • Image Size (in megapixels or MP)
  • Image Compression

Let us look at these in more detail.

Image Size

This refers to the total pixels that are used to create the image. Just bear in mind that this number is not resolution since many erroneously use this term. With this option, you can record an image with fewer pixels than what your camera is specified for. E.g., if you have a 16MP camera, you can also record images at 9MP and 4MP, apart from images at 16MP.

In the author’s opinion, this setting is best forgotten after choosing the maximum number of pixels that the camera has to record the image. After all, you have paid for all those megapixels; hence why discard so many of them? If that is the case, you may ask why do manufacturers provide this option at all? This is mainly because it is easy to transfer smaller files over the net.

Hence if you are using images for Web publishing, it is better to keep the pixel count low to load quickly in the browser. Remember that most monitors do not have a pixel count greater than 2 MP, so anything above is a waste. So, if your need is purely Web publishing, you can get away with a smaller size image.

However, there is a significant pitfall. If later you want that same image to be printed large, the recorded image will not have the job pixels. This is why I recommend you do not use this option. Remember, you can always make an image smaller (fewer pixels) in post-processing, but you cannot do about the reverse without losing quality.

Most cameras record a smaller image in JPEG only, while RAW is recorded at full pixel count. However, of late, a few cameras record a smaller RAW file as well. If you record a RAW and a JPEG, you can record a smaller JPEG (with will lesser pixels and higher compression) independent of the RAW image. This is mainly to conserve memory card space since you also have a full pixel count RAW available to you for downstream applications. However, if you photograph with a smaller RAW file, there will be no going back.

Image Compression

Sometimes this is called the ‘Quality’ setting though it is only one of the three parameters that affect the overall quality. This is the second set that affects the image’s size and quality, apart from the image size setting.

After the sensor captures an image, your digital camera’s onboard computer adds color information. It then processes the image using the various parameters that you have chosen in the camera. These include saturation, contrast, sharpness, white balance, etc. The processed image is then “compressed” (that is reduced in size) by the camera’s onboard computer and written as a JPEG file in the memory card inserted in your camera.

JPEG is essentially a “lossy” format. Thus, there will be a loss of data, and hence the quality of the image will suffer, mostly if a high compression ratio is chosen. The loss of quality typically shows up as ‘artifacts’, unwanted features that were not initially present in the image.

Also, unless you have a very compelling reason, please always use the least compression for the highest image quality. Remember that you can always compress the image to a higher ratio and a smaller size later with post-processing. Still, the reverse is not possible without loss of overall quality.

Most cameras offer three “grades” or settings for compressing your files in JPEG format. The names could differ from manufacturer to manufacturer.