Normally we use data compression step for storing an image in a digital storage device. When you need to learn photography, you better have the basic knowledge of the image storing in a digital storage devices. Basically image it can be divided into 2 types, according to the method of compressing data of images. That is,
- Lossless type
- Lossy type
When we consider lossy Vs lossless image file compression, both have pros and cons. When you learn photography field, better you should have a basic knowledge about those two sections for choosing the better option that according to your requirements. Let’s move to Lossy type image compression.
Lossy type image compression
Simply we can describe the basic idea of the lossy type image format compression is when you store image data in digital storage devices, these type images goes under compressing step. Therefore it’s some data will reduce. When it gets back for preview from the storage (expanding procedure) we cannot open the original image again. This is an irreversible procedure. Therefore we never get expand original image again. When we do this compressing function, again and again, data will reduce again and again.
Basically, image is made out with millions of color pixels. In this type of compressing, color pixels change the color level to the closer pixels’ colors. Therefore some shaper points and outlines will reduce than the original image.
Especially Lossy type images can be used in streaming media and internet telephony. Because of lower file size. Then we can increase the loading speed of the web pages and website too. You can compare the below photographs. First one is the original image and the second image is the previewed image from the digital storage.
In the first image, you can see the sharp lines and perfect outlines clearly. But the second image some outlines and shaper edges became to smoother than the original. Then you can understand the behavior of Lossy type image storing, the colors of the pixels were changed and lost some data or information from the original image.
Advantages of Lossy image compression
- Very small file sizes and lots of tools,
- Need small capacity of storages.
- Plugins and software support it.
- Much better for websites images.
Disadvantages of Lossy image compression
- Quality degrades with the ratio of compression.
- Can’t get original image back after compressing.
- The image file is compressed more, again and again, the higher risk of perceptible differences.
- Not suitable for high-quality large size printing purposes.
Example image formats for Lossy type: PNG, JPEG and GIF
Therefore there is no any reduction of any data or information from the original image. Then we can preview again the original image back, without reducing the original quality. Sharp points, borders and edges appearance can be seen as the original image. However, this lossless type image file size is too large and it is higher than the lossy type. Lossless images need more storage capacity.
DSLR camera has an option to save high-quality images from the Lossless type of image formats. Such as RAW format and TIFF format. (If you need to learn about the image file formats, you can refer my “Image File Formats” article.
This type of images can be used for large-scale banners, other printing purposes and especially for professional photography too without considering the how many times save again and again in a digital storage devices.
Advantages of Lossless image compression
- No loss of quality, data or information from the original image.
- Best for large-scale printing purposes.
Disadvantages of Lossless image compression
- Larger files than if you were to use lossy compression.
- Smallest reduction in file size, therefore need large digital storages.
Example image formats are RAW and TIFF
Lossy Vs Lossless image file size comparison
According to the photographers’ requirement, the DSLR camera choose the saving type of image file formats. Such as JPEG, RAW or TIFF image file formats with different quality levels. We will give the size comparison of DSLR camera’s JPEG image and RAW image.
- 21Mpixel – RAW – 22MB
- 21Mpixel – JPEG – 4.4MB
Normally DSLR camera provides 3 option for saving as the JPEG image file. That is,
- Superfine (very low level of image compression)
- Fine (moderate level of image compression)
- Low fine (high level of image compression
According to those options, we can change the image quality and size of the photograph easily. Superfine image’s data losing a level is very low and file size is considerably high.
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